I
9 312966 1 23633
Feels like a scope.
Sets up like a scope.
Displays like a scope.
Could this really be a
logic analyser?
Sixteen channels of 500 MSa/s
logic analysis in a box that
drives like a scope may seem
impossible. Until you see the
HP 54620A logic analyser.
Will this setup
procedure convince
you?
Connect the inputs, hit
autoscale, look at the display.
You’ll get the benefits of logic
analysis - including advanced
triggering - without the
learning curve.
The HP 54620A will
change your attitude
about troubleshooting.
Its range of triggering allows
you to match the complexity
of your problem. The high¬
speed display system shows
you unstable signals. And
because of its remarkably
rapid display update rate and
instantaneous feedback, you
can operate this with a simple
twist of a knob.
The HP 54620A - a logic
analyser that really is as easy
to use as your scope. A pretty
convincing case.
So call our Customer
Information Centre on
13 1347 (Australia wide) and
ask for extension 2902.
A better way.
HEWLETT®
PACKARD
READER INFO NO. 1
Volume 57, No.6
June 1995
No glasses’ 3D video
Perth-based Xenotech Australia has
attracted interest from all around the
world, for its patented projection 3D
system which requires no special
glasses. Already Korea's giant Sam¬
sung Electronics has signed a $1 mil¬
lion licence agreement, as we explain
in our story starting on page 26.
Chess in a matchbox
One of our projects this month is this
single-chip chess computer ; which is
so small that it will fit in a matchbox,
along with its battery (but not the
chessboard, of course!). See our
story, starting on page 68.
On the cover
Graham Cattley, who recently joined
EA’s editorial team as a project de¬
veloper and writer, is seen inspecting
a CD-ROM drive before it was in¬
stalled in the editors PC, as part of a
‘multimedia' upgrade. See our story
on upgrading, starting on page 12.
(Photo by Peter Beattie.)
Video and Audio
6 WHAT’S NEW IN VIDEO & AUDIO Compact new Super VHS camcorder
8 THE CHALLIS REPORT Akai's impressive VS-G2100 Intelligent' VCR...
26 BIG SCREEN 3D TV NEEDS NO GLASSES Australian development!
28 COMPACT VIFA SUBWOOFER KIT Uses the new 200mm bass driver
Features
12 UPGRADING YOUR PC WITH A MULTIMEDIA’ KIT Avoiding the pitfalls
24 MOFFAT’S MADHOUSE A little slice of heaven, in Denver
32 INTRODUCTION TO BASIC ELECTRICITY Book and video from DSE
34 WHEN I THINK BACK... A.C.E. Radio and the post-war disposals stores
Projects and Technical
20 AUTOMOTIVE ELECTRONICS Using a scope for vehicle faultfinding — 2
46 THE SERVICEMAN The car that produced wow and flutter in cassette players!
50 CIRCUIT & DESIGN IDEAS Oil temperature indicator, flashing beacon
54 DSE DISCOVERY SERIES’ KIT: Parallel port interface for PC's...
60 CFL & FLUORO LAMP INVERTER Low cost, easy to build, flexible too
68 SINGLE CHIP CHESS COMPUTER So tiny, it fits in a matchbox
74 VINTAGE RADIO Rewinding old power transformers
91 EXPERIMENTING WITH ELECTRONICS Putting transistors to use
Professional Electronics
100 NEWS HIGHLIGHTS Griffith University to scan historic pictures of Queensland
104 PC-BASED 68705K1 PROGRAMMER Low cost unit interfaces via printer port
107 NEW PRODUCTS MATV amplifier, audio line & speaker switch boxes
110 SOLID ST ATE UPDATE IDE interface for 8-bit micros; 750MHz op-amp chip
112 TEST & MEASURING FEATURE: Fluke's enhanced ‘Series IP Scopemeter
116 TEST & MEASURING FEATURE: HP's new 54620A Logic Analyser
119 TEST & MEASURING FEATURE: Roundup of the latest products
124 SILICON VALLEY NEWSLETTER Gates & Spielberg in ‘interactive' venture
126 COMPUTER NEWS & NEW PRODUCTS Hex speed CD-ROM drive...
Columns and Comments
4 LETTERS TO THE EDITOR Computer museum, colour TV milestone
5 EDITORIAL VIEWPOINT The rise in cover price that we really couldn't avoid...
40 FORUM The fury of some radio amateurs, when their wallets are threatened
83 SHORTWAVE LISTENING BBC monitors the world for news
84 INFORMATION CENTRE Party pieces, magnetics and high voltage capacitors
Departments
82 BOOK REVIEWS 130 DIRECTORY OF SUPPLIERS
96 MARKETPLACE 130 ADVERTISING INDEX
98 EA HISTORY, CROSSWORD 77,94 NOTES AND ERRATA
ELECTRONICS Australia, June 1995
3
MANAGING EDITOR
Jamieson Rowe, B.A., B.Sc., SMIREE, VK2ZL0
GRAPHICS/PRODUCTION EDITOR
Mille God den
TECHNICAL EDITOR
Rob Evans, CET (RMIT)
PROJECT DESIGNER/WRITER
Graham Cattley
CONTRIBUTORS
Louis Challis
Arthur Cushen, MBE
Peter Lankshear
Jim Lawler, MTETIA
Tom Moffat, VK7TM
Peter Phillips, B.Ed., Dip Ed., ECC
Nick de Vries, MIAME, AMSAE
Neville Williams, FIREE, VK2XV
DRAFTING
Drawquick Computer Graphics
COVER DESIGNER
Clive Davis
PRODUCTION
Ray Eirth
CIRCULATION MANAGER
Michael Prior
PUBLISHER
Michael Hannan
ADVERTISING MANAGER
Selwyn Sayers
Phone (02) 353 0734; fax (02) 353 0613.
ADVERTISING PRODUCTION
Karla Dixon, phone (02) 353 0713
SECRETARY
Anna Maria Zamora
HEAD OFFICE - EDITORIAL
P.O. Box 199, Alexandria 2015.
180 Bourke Road, Alexandria 2015.
Phone; (02) 353 0620. Fax: (02) 353 0613
Reader Services: Phone (02) 353 0620
Subscriptions enquiries: phone (02) 353 9992
Book Shop enquiries: phone (02) 353 9944
INTERSTATE ADVERTISING OFFICES
MELBOURNE: 504 Princes Highway, Noble Park,
Vic 3174. Phone (03) 213 3222.
Fax: (03) 701 1534, Pilar Misa.
BRISBANE: 26 Chermside Street, Newstead, Qld
4006. Phone: (07) 854 1119.
Fax: (07) 252 3692, Graham Smith.
ADELAIDE: 98 Jervois Street, Torrensville, SA
5031. Phone: (08) 352 8666,
Fax: (08) 352 6033, Kerryn Delaney.
PERTH: Allen & Associates, 54 Havelock Street,
West Perth, WA 6005. Phone: (09) 321 2998,
Fax (09) 321 2940, Tony Allen.
UNITED KINGDOM: John Fairfax & Sons (Aust),
12 Norwich Street, London, EC4A 1BH.
Phone: (71) 353 9321, Fax: (71) 583 0348
ASIA: Headway Media Services Ltd, Room 2101,
Causeway Bay Centre, 15-23 Sugar Street, Hong
Kong. Phone: 516 8002,
Fax: (862) 890 4811, Adrian Batten.
ELECTRONICS AUSTRALIA is published by
Federal Publishing Company a division of
Eastern Suburbs Newspapers Partnership,
which is owned by
General Newspapers Pty Ltd.
A.C.N. 000 117 322,
Double Bay Newspapers Pty Ltd.
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Brehmer Fairfax Pty Ltd.
A.C.N. 008 629 767,
180 Bourke Road, Alexandria, NSW 2015.
Copyright © 1994 by Federal Publishing
Company, Sydney. All rights reserved.
No part of this publication may be reproduced
in any way without written permission from the
Publisher or the Managing Editor.
Printed by Macquarie Print, 51 - 59 Wheelers
Lane, Dubbo NSW, 2830, phone (068) 843
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Distributed by Newsagents Direct Distribution
Pty Ltd, 150 Bourke Road, Alexandria, NSW
2015; Phone: (02) 353 9911.
ISSN 1036-0212
♦Recommended and maximum Australian
retail price.
The Australian Publication emblem on the front cover of
this magazine is there to signify proudly that the
editorial content in this publication is largely produced
and edited in Australia, and that most of the advertise¬
ments herein are the products and services available
within Australia.
LETTERS TO
THE EDITOR
Boxes not squiggles
It’s high time, I feel, that the old con¬
troversy be resurrected. Since it last got a
run, you have taken over copyright to the
Elektor files, and they’ve been using rec¬
tangles as symbols for resistors, since
Adam picked up his soldering iron.
We who use a drawing template for
this, find it much easier and quicker than
either hand drawing a ‘squiggle’, or using
rubdown symbols from a pre-printed
sheet. Much cheaper, too!
Many people though that your early
opposition to boxes was perhaps a trifle
xenophobic. That is, those of us unfinan-
cial enough to decide we can live without
fancy CAD facilities.
Can we please have a rethink about the
pragmatism? Surely, many people are
dissuaded from submitting circuits, be¬
cause of a perceived bias, that “it’s got
boxes — it won’t be printed!”
Come on, all you manual draughting
designers. Let’s hear it for boxes, not
squiggles!
Peter Lucock,
Wynnum, Qld.
Comment: We don't have any rights to
Elektor files , Peter. If we get a reasonable
number of requests for 'box' symbols
rather than 4 squiggles \ as you call them ,
we'll certainly consider changing. Frank¬
ly though, we prefer our circuits to show
component function , if possible.
Computer museum
The Australian Computer Museum
Society was formed to preserve early ex¬
amples of computer hardware and
software. Although we are attempting to
collect all types of equipment, one of
our main briefs is to preserve ex¬
amples of Australian development and
manufacture.
Although many people in industry are
glad to help, some still suffer from the
‘technological cringe’ and many valuable
early examples of Australian expertise
are being tossed out.
We welcome information from your
readers regarding ANY Australian com¬
puter development project they were in¬
volved in, for our database. We then
can attempt to collect historic details
or, if possible, the actual artifacts! It
is surprising what people still have got
tucked away under their bench.
Remember, today’s junk is the future’s
historic artifact.
We are also interested in a list of ‘top
ten’ items that we should collect, and it
would be interesting to get some input
from your readers with their own ‘list’.
We are not just interested in hobby or IT
equipment, but all aspects — including
embedded processors such as washing
machine controller cards, etc.
A good starting point would be your
EDUC-8 computer, published in EA
many years ago. This unit would have
been the first introduction to computers
for many of your readers. Another ex¬
ample is the Philips PSF200
microprocessor based traffic light con¬
troller developed in 1972. There must be
many more.
Although we will of course, collect ex¬
amples of the American Digital Equip¬
ment PDP-8, etc., they are being
collected in many other places in the
world — almost nobody else is collecting
Australian computers.
One final item. We are fast running out
of space to store our artifacts, so if
anyone has a huge empty storage area
they are not using — please let us know!
If any readers are interested in the
above project, please contact John Rich
on (02) 569 4965.
John Rich,
5 Queen Street,
Petersham, NS 2049.
CTV milestone
While I realise this letter may not be
published until about May or June, none¬
theless I’m writing to express disappoint¬
ment that your March 1995 edition of
Electronics Australia did not acknow¬
ledge the important milestone that oc¬
curred that month.
It was on March 1st 20 years ago that
Australian television service made a
quantum leap forward, by switching to
full colour broadcasting.
This event was as important to the
medium of television in this country as
the beginning of the medium itself, when
Station TCN-Sydney commenced trans¬
mission on 201-208MHz (VHF Ch.9) in
September 1956, followed by a short
time later by Station GTV-Melbourne on
the same frequency range.
For my part I wrote a letter to the
Federation of Australian Commercial
4
ELECTRONICS Australia, June 1995
Television Stations advising them of this
anniversary as well as ringing the three
local broadcasters in my region: NBN,
Prime and NRTV (now calling itself
TEN-Northern NSW — to be honest, it
was a daft move by them to take on
their Sydney feeder’s identity, but what’s
done is done) to advise them directly of
this important date. Whether they do any¬
thing with it or not is up to them (I’m
writing this at about 4.45 PM on the day
in question).
It seems to me that for all the publicity
surrounding the event at the time, surely
20 years later the event could’ve been
revisited and celebrated in a reasonable
low key fashion.
There is no need to throw streamers,
blow up balloons and have extravagant
parties to celebrate the event, but, none¬
theless, a milestone such as this deserved
some recognition. This would’ve made
up for the total lack of recognition for the
first, fifth, 10th and 15th anniversaries of
this event, in 1978, 1980, 1985 and 1990
respectively.
OK, now that I’ve gotten that bit
of information in, I have a couple of
other things to do in this letter. First
I would like to apologise to Tom
Moffat for inadvertently misleading
him on Station 2-TM Tamworth and
their conversion to FM. On a trip to
the region in February of 1994 (Gun-
nedah, to be precise), I had occasion
to pick up 2-TM’s FM broadcast. This
together with seeing the station’s FM
logo in a TV promotion for the schools’
Rock Eisteddfod, led me to believe
— wrongly, as it turned out — that
2-TM had indeed converted to FM
and departed from their AM spot. I have
since learned that 2-TM operates two ser¬
vices in the area, one a youth oriented
(perhaps) FM service and the other, their
long standing original AM service, com¬
plete with Nick Erby’s Country
Hoedown! My apologies, Tom! Can you
ever forgive me?
Neil Forbes,
Stockton, NSW 2295.
Letters published in this
column express the opinions
of the correspondents con¬
cerned, and do not neces¬
sarily reflect the opinions or
policies of the staff or pub¬
lisher of Electronics
Australia. We reserve the
right to edit letters which are
very long or potentially
defamatory.
EDITORIAL
VIEWPOINT
The rise in cover price
that we couldn’t avoid...
As you’ve no doubt discovered by now, we’ve finally had to increase the
cover price of Electronics Australia , and with this issue.
While price rises are never easy to accept in any product, this is in fact the
first rise we’ve had for just on four and a half years. (We’ve been able to hold
the price at $4.95 since January 1991.) Although there have been inevitable
rises in many of our costs during that period, by careful belt-tightening we’ve
managed to absorb these, so that they didn't have to be passed on to our
readers. But in the last few months a significant change has occurred, in an
extremely basic and crucial area as far as publishers are concerned: world wide
paper supplies and costs.
People in other industries may not have noticed, but towards the end of last
year many grades of paper became both harder to obtain, and more expensive
especially the stocks in common use for magazine, newspaper and
catalogue production. The reason for this seemed to be that many of the
world’s economies had begun to move out of recession, and the increased
demand had both drained supplies and forced up the prices.
Since then, the situation seems to have worsened, particularly in Australia_
where two local paper mills announced that they were ceasing production of
two of their most popular grades (one of which was the very stock we’ve used
to print many of the pages in EA, for many years). Apparently this was done so
that the mills could maintain their output of other stocks, particularly to large
newspaper publishers.
In consequence, magazine publishers like our own company Federal
Publishing have been forced to seek paper supplies from overseas mills, and
inevitably pay a premium in terms of both the price ex-mill and the costs of
transporting the paper to Australia. This has meant that in the last few months,
we have seen the effective price of our paper rise by nearly 50% (with further
rises predicted).
Needless to say, we simply couldn’t afford to absorb an increase of this mag¬
nitude. So there were really only two options, if we were to remain viable as a
publication: either reduce the size of the magazine (i.e., fewer pages), so that it
used less paper, or keep it the same size, but increase the cover price instead.
Neither option was desirable, of course, so we faced a proverbial ‘heads we
lose, tails we don’t win’ situation...
Although we knew that no one would welcome a price rise, we ultimately
decided that EA s readers would prefer a modest rise to seeing their magazine
chopped back in size, or perhaps not able to continue at all. Particularly if we
tried explaining the situation, as openly and as honestly as possible.
So that’s the background to this price rise, which really couldn’t be avoided.
We deferred it for as long as we could, but finally it was forced upon us. I
suspect that you 11 see a similar or greater rise in the price of most other
magazines, if they haven’t already done so by the time you read this.
Jim Rowe
ELECTRONICS Australia, June 1995
5
What's New in
VIDEO and AUDIO
Integrated home
theatre system
Sony has released a home theatre
sound system which is claimed to in¬
corporate everything needed to
generate ‘cinema sound’, in one sleek
integrated package.
The Sony SA-VA3 eliminates the
need to buy individual component
units and the many cords and leads
often required to connect such a
system together. It incorporates a Dolby
Pro-logic Decoder, multi-channel
amplifier, two subwoofers and all
other speakers inside a pair of neat
stylish tower enclosures.
“This new active speaker system
takes us into the next generation of
home theatre. In the 80s, home enter¬
tainment consisted of a television,
video cassette recorder and a hi-fi sys¬
tem. We then started buying centre and
rear speakers and
Dolby Pro-Logic
receivers which
generated the
sound around the
room,” said Sony’s
Product Manager
for hi-fi, David
Allen.
“The new SA-VA3 sound system has
all the features and functions of separate
component systems minus the fuss and
bother of connection. The system is also
stylishly designed to compliment any
living area,” he said.
The SA-VA3 is easy to connect, as
only a single cord is required to connect
both main speakers, supplying sound
and power. The TV, VCR or laser disc
player is simply connected to the SA-
VA3 via the audio line outputs. Your
‘Home Theatre’ can be set up in less
than 15 minutes.
Ideally, to generate the best sound
possible, the towers should be placed on
either side of the TV and the supplied
rear speakers placed on the left and right
behind the viewer.
The built-in amplifier is designed to
match all drivers perfectly, in order to
provide maximum performance for the
channels. Seven separate amplifiers are
used, improving sound quality and bass
response, and also improving the chan¬
nel separation between the five
speakers. Total power output is 170
watts and major functions can be
operated by the supplied remote control.
The Sony SA-VA3 is available at
Sony ‘Elite’ stores for an RRP of $2299.
Innovative features in new colour TV’s
Two new colour televisions from Mitsubishi are made to
order for the seriously laid back viewer. Not only do the
new TV’s automatically adjust picture quality according to
where you sit and how much light is in the room, but they
can turn to the left or right via remote control. A special
bonus for parents who wish to control when the TV goes on
in their household is Mitsubishi’s Child Lock.
Fuzzy logic technology, borrowed from Mitsubishi’s top
of the range DIVA TV, automatically responds to room
lighting and the viewer’s position to optimise picture
quality. The Auto Turn facility, also previously only avail¬
able on the DIVA, allows viewers to adjust the viewing
angle via remote control. At the touch of a button, the set
can be turned by up to 15° in either direction.
Known as CT-29AX1 and CT-25AX1, the new models
have 68cm and 59cm screens respectively. Other DIVA
technology used in the new models include picture im¬
provement circuitry to provide improved contrast, and high
resolution. Improved sound quality is also achieved with
enhanced bass and a three way surround sound processor.
The AX1 series also features the ‘Worldwide Multi 28
System’, which allows viewing of broadcasts or videotapes
from around the world without the need for a multi system
VCR. Optional upgrades include picture in picture or
Teletext. Recommended retail prices are CT-29AX1 $1999;
CT-25AX1 $1699.
6
ELECTRONICS Australia, June 1995
Compact Super VHS camcorder
Panasonic has released a new compact Super VHS cam¬
corder called the NV-S90A, targeted at enthusiasts who
want high quality video productions in an easy to use and
compact format.
The S90 has high picture and sound quality, with hi-fi
stereo and the Super VHS-C format, which is superior in
quality to standard VHS. It also incorporates a new CD
image sensor featuring a full 680,000 pixels (a conventional
camera has 420,000 pixels).
A variety of digital functions, including the new ‘Super
Image Stabiliser’ and 20X digital zoom, allow the user to
enhance video productions. Other functions include Digital
Mix, Digital Wipe, Digital Strobe, Digital Gain-up and
Snapshot Record. Digital Zoom takes over from the optical
zoom at 10X magnification and covers the 11X to 20X
zoom range.
The built-in time base corrector (TBC) reduces picture in¬
stability known as ‘jitter’, thus improving the vertical pic¬
ture information without replacing the original
synchronisation signals.
The S90 also features VITC (vertical interval time code)
‘Read’ and ‘Write’ functions, to provide professional grade
editing time coding by giving each picture a time code. An
Audio Dubbing mode also allows creative editing. Other
features and functions include a single switch start, on¬
screen menu, large on-screen display, one piece aluminium
diecast chassis and auto date recording.
The NV-S90A camcorder is available from electrical
retailers and duty free outlets for a recommended retail
price of $2999.
Twin-wall speaker systems
Sydney-based firm Architectural
Audio Design, which specialises in the
design, supply and installation of built-
in audio systems, has released a number
of new products from specialist US
manufacturer Sonance.
The three-way D6000 system is now
the ‘flagship’ model in the Sonance in¬
wall speaker line, combining a 200mm
dual voice-coil woofer with a 63mm
poly cone midrange driver and a pivot¬
ing 18mm aluminium dome tweeter,
with ferrofluid cooling and twin
neodymium magnets.
The D6000 has a nominal impedance
of 6£2, a power handling capacity of
from 5W to 100W, an efficiency of
91dB (lW/lm) and a frequency
response of 39Hz - 21kHz +/-3dB. It
also provides eight selectable level set¬
tings for the tweeter, four for the
midrange and eight for the woofer —
giving a high degree of flexibility for
optimisation in a given environment.
External dimensions are 254 x 407 x
77mm, and the D6000 requires a cutout
of 378 x 225mm.
The D5500 is also a three-way sys¬
tem, virtually identical in size to the
D6000 and with similar ratings. How¬
ever in this case the pivoting 18mm fer¬
rofluid cooled tweeter uses a soft dome,
while the 63mm midrange driver has a
treated paper cone. The rated frequency
response is 39Hz - 20kHz +/-3dB, with
an efficiency of 90dB (lW/lm). The
switch panel provides over 60 settings
for room optimisation.
Next in the line is the D5000, again a
three-way system but with a 15mm
pivoting poly dome tweeter, and a
power rating of 5 - 75W. This system
has a rated frequency response of 45Hz
- 20kHz +/- 3dB, a nominal impedance
of 8Q and an efficiency of 90dB
(1 W/lm). The D5000 has a switch panel
providing 15 settings, and its external
dimensions are the same as for the other
two models.
Other new products in the Sonance
line include the SIR, a two-way round
system combining a 172mm poly¬
propylene cone woofer with a con¬
centric 50mm cone tweeter, and the
VC 101 and VC51 — two new switched
low impedance stereo volume con¬
trols, featuring 12 level settings (max
attenuation -42dB) and power ratings
of 100W and 50W per channel
respectively.
Further information on the Sonance
range is available from Architectural
Audio Design, Suite 3A, 600 Military
Road, Mosman 2088; phone (02)
968 3299, or fax (02) 968 2548.
Personal CD
player from Sanyo
Sanyo has released four new personal
CD players, two of which feature an
anti-shock system to allow uninter¬
rupted listening while jogging, walking
or driving over rough ground.
The top of the range model, CDP-67,
has a digital anti-shock system with 2.4
second shock compensation memory
and a wired remote control unit for easy
control over volume and main player
functions. With a 22 track random
memory, repeat function and pre-
programmable facility, you can play
back your music in any order you like.
A DSP (digital sound processor) system
is included, providing three preset sound
patterns for enhanced music realism.
Other features include a multi-func¬
tion LCD with a two digit current track
number indication and time elapsed/
time remaining indications. For easy
reading at night the display is backlit.
A special hold switch stops the player
from going into operation mode ac¬
cidentally when the player is carried in a
pocket or bag, while the automatic
power off function saves batteries by
switching the player off when the disc
ends. All the models in the range have
‘line out’ sockets which means the units
can be connected to a larger audio sys¬
tem when you don’t require portable
sound.
Retail prices are: CDP-67 $449, CDP-
60 $399, CDP-47 $259, and CDP-41
$249. ❖
ELECTRONICS Australia, June 1995
7
Video & Audio: The Challis Report
AKAI'S VS-G2100
'INTELLIGENT' VCR
This month Louis Challis turns his critical attention towards the current top-of-the-line model in the
Akai range of video cassette recorders. The VS-G2100 offers many impressive features, coupled with
outstanding performance — but may possibly represent 'over kill for those who find themselves a
little intimidated by modern electronic gadgetry...
Early in January 1991, I caught a late after¬
noon US air flight from Las Vegas to Los An¬
geles. The hostess seated me next to a young
man, who quickly involved me in conversa¬
tion. One of his first questions was whether I
had enjoyed the Winter Consumer Electronic
Show (CES)?
I blinked, and inquired how did he know
that I had been to the CES? He responded that
the large bag of what appeared to be paper¬
work that I had placed in the baggage cubicle,
was the only real clue that he had. I rejoined
by asking him, whether he too had been to the
CES and if he had, what was his particular in¬
terest in electronics?
A strange tale soon unfolded. I discovered
that this young man had come to the CES with
the express purpose of learning as much as he
could about the complexities of the new con¬
sumer electronic equipment, which were
about to be released on what he referred to as
the 'unsuspecting public'. These complexities,
it seems, had created a new and relatively in¬
novative market for his talents.
He boldly recounted how he advertised
his services in the local papers of Los An¬
geles, as well as by way of letter drops, sell¬
ing his services to those unfortunate people
who couldn't understand the handbooks of
their new and expensive electronic applian¬
ces. He explained how he had turned what
had initially been unsolicited requests from
neighbours, to explain to them how to use
their equipment, into a full time profession.
The more complex the equipment (or its
remote controllers) became,
the more quickly his market
grew. A significant proportion
of his clients were widows
whose husbands had previously
fulfilled such chores, and now
these poor widows were being
dragged into 20th or 21st cen¬
tury, with what he described as
being a 19th century com¬
prehension of electronics.
The young man went on to
gloat that, not only was he
making a living, but his reputa¬
tion was being spread by 'word
of mouth'. Each successive
generation of more advanced
remote controls or related 'state
of the art' advances in VCR
technology had created a burgeoning market
for his talents.
Not surprisingly, almost every revolution
generates a counter-revolution. The
electronics revolution with its microproces¬
sor controls and associated remote controls,
with improved and RF links, has created the
counter-revolution. The market place now
cries out for 'more user friendly' equipment
which caters for people of all ages. Unfor¬
tunately it appears that the young have no
problems; it is only the older or elderly
members of our society whose noses appear
to be 'put out of joint'.
Akai was amongst the first of the VCR
manufacturers to realise that its intending pur¬
chasers wanted equipment which was easier
to use.
The company's marketers realised that a sig¬
nificant proportion of the more affluent pur¬
chasers have failing eyesight, that many are
now forced to wear glasses for the first time in
their lives, and they have difficulty in reading
the symbols on the remote control.
In 1982 Akai introduced the first Interactive
Monitor System (IMS), which provided large
on-screen displays and simple programming
instructions, in their model VS-2 VCR. I
reviewed one of the first of those VCRs, and
was impressed by its convenience and by its
sensible ergonomic features.
Whilst many other manufacturers have fol¬
lowed that lead, it seems that Akai has consis¬
tently been 'at the head of the pack'. They
have continued the development of innovative
concepts, with the aim of producing a better
product that is easier to use.
As you may have observed, one problem
tends to be that when any product sets out
to outdo its competitors, then the general
corollary tends to be that its complexity is
similarly increased. Ultimately this leads to
more buttons, bells and whistles, and the
product that started off having attributes of
simplicity and ease of use, tends to drift in
the other direction.
The new Akai VS-G2100 video cassette re¬
corder manifestly exemplifies this trend, and
although it is a fine VCR, its buttons, bells and
whistles turn it into a relatively complex piece
of equipment, which ends up being best suited
for the person who is computer literate, or
who adores gadgets.
The VS-G2100 is the latest, and unques¬
tionably the greatest, of a long line of top
quality Akai VCRs. It incorporates more than
30 special features, many of which must be
regarded as being 'state of the art'.
Its primary features can be summarised
as follows:
• Two-speed recording and playback (i.e.,
standard speed and long play, which
provides the ability to record up to eight
hours of video on a quality four-hour tape).
• Super intelligent HQ, which is the most
important feature of this recorder. This was
an Akai development, and provides sig¬
nificant improvements in recording quality.
Super intelligent HQ is based on the prin¬
ciple that the VCR will automatically
evaluate the magnetic char¬
acteristics of any tape used
during its initial phase of
recording. The recorder then
re-adjusts the recording sig¬
nal strength, as well as the
RF bias signal to optimise
the subsequent recording
process. The VCR also incor¬
porates the current AUTO
CHROMA CONTROL
(CACC) circuit, which
reduces colour saturation
problems. These normally
manifest themselves as
colour smear, and with well
defined quality pictures, can
be disturbing.
• Intelligent HQ on playback,
Measured performance of VS-G2100 Video Cassette Recorder
Serial No. B9465-00516
Frequency response SP 10Hz to 20kHz +0.3 -2.4dB
LP 10Hz to 20kHz+0.2 -2.0dB
Harmonic Distortion (in SP Mode at indicated level)
Distortion
100Hz
100Hz
1kHz
100Hz
6.3kHz
Component
OVU
-20VU
OVU
-20VU
OVU
2nd
-61.3
-65.2
-42.5
-56.2
below
3rd
-
-
-43.9
-66.9
the
4th
-75.5
-69.7
-47.5
-
noise
5th
-80.7
-
-58.2
-
threshold
THD%
’ 0.89
0.064
1.1
0.16
Signal to noise ratio SP -77dB(A) -67.5dB unweighted
LP -72dB(A) -60.0dB unweighted
8
ELECTRONICS Australia, June 1995
plus a detail enhancer circuit which en¬
sures that there is minimal distortion,
through the use of a refined 'linear
feedback' equalisation circuit, supple¬
mented by a linear noise cancellation cir¬
cuit. The nett result is a cleaner, sharper
and more finely controlled playback sig¬
nal, and as I can attest, the results are
readily observed in A-B testing.
• On-screen programming, with a choice of
eight languages including English, German,
Spanish, Italian, Dutch, Swedish and most
surprisingly, Finnish. This feature is of min¬
imal advantage in Australia, but is a real
plus in Europe. The language change is
achieved through the use of an on-screen
menu, as are most of the other critical
functional changes.
• G-Code simplified programming is incor¬
porated in the remote control, as are some
40 other functions. The remote control is
neat, attractive and functional. It incor¬
porates its own LCD display and time
clock, with controls divided into two main
groupings. Those which are frequently re¬
quired for channel changing and related
functional controls are placed on the exter¬
nal casing, while other less frequently re¬
quired controls are placed under a cover.
The G-Code function is very simple in use,
and I believe will ultimately be adopted as
a Universal feature on all medium perfor¬
mance and 'top of the line' VCRs.
• Quick Servo Drive, which speeds up the
recording startup process to less than one
second following the placement of the
video cartridge into the recorder. This
works exceptionally well.
• An NTSC playback facility, so that NTS
videos can be replayed on an existing TV
which is designed for PAL format recep¬
tion. This is a real plus, particularly if you
don't wish to purchase a more complex
and more expensive TV set or monitor.
• Digital Stereo sound recording, with full
control over the audio channel's recording
levels, using the multiplex hi-fi stereo
capabilities. The digital stereo signal
quality is outstanding, as I discovered, and
offers a cost effective alternative for
recording high quality music — with up to
eight hours of playback.
• Flickerless Still and Slow Motion Replay,
and also Jog Shuttling on the front panel
and via the remote control. To achieve true
flickerless control, the manual controls on
the remote control must however be used
to achieve the best performance.
• Quick Timer or Simple Timer program¬
ming, with the ability to record eight
programs sequentially.
• The VCR is pre-tuned for channels 2, 7, 9
and 10, with a delightfully simple automat¬
ic tuning procedure for setting other chan¬
nel frequencies that may be required —
i.e., channel 28 in Sydney.
Other features which I felt most users would
value include:
• External video and audio input jacks on
the front panel.
• A microphone socket on the front panel for
audio dubbing, when adding dubbed or
new sound tracks to an existing pre¬
recorded video.
• Multi-speed forward and reverse video
playback, with transport speeds as high as
seven times normal play speed.
• A 'real time' counter, displaying elapsed
time in minutes and seconds, which can
be displayed on the upper RH corner of
the monitor screen.
• A remaining time indicator displays
how much recording time is left on the
tape (but without the precision of the real
time counter).
• A quick timer and sleep timer, to expedite
switching on and/or simplify switching the
VCR off.
• An auto head cleaner which automatically
cleans the head when a tape is loaded or
unloaded. Most Akai video recorders now
offer this as a standard feature.
• A DEMO MODE facility is incor¬
porated, so that with a pre-recorded tape
loaded the VCR will demonstrate many —
but not all of its most important features
to the user.
The plastic moulding of the remote control
has been tapered, and has a sensible shape
that fits well in the hand. It provides normal
channel selectors (UP or DOWN), PLAY,
STOP, FAST FORWARD, REWIND, RECORD,
and PAUSE/STILL together with POWER
ON/STANDBY, TV or VCR, an EJECT button,
and INDEX FORWARD and REVERSE buttons.
The Jog Shuttle's rotary control knob at the
lower end of the remote control is smooth and
effective. The vast majority of special functions
can only be accessed by means of the remote
control, and the majority of those special func¬
tions are accessed by lifting the hinged cover.
With the cover raised, a further 28 pushbut¬
tons and four directional controls are immedi¬
ately accessed. Many of these pushbuttons and
controls provide dual functions. They do
however provide tremendous control
flexibility, and as I found, the potential power
increases as you become familiar with the
idio- syncrasies of the system.
When first reading the handbook, some in¬
tending purchasers could well be discouraged
by the 40-odd pages of detailed instructions.
Unfortunately, when a piece of equipment
contains as many features as the VS-G2100,
those instructions are absolutely essential.
Whilst Akai may have intended that this VCR
be described as 'user friendly', I suggest that
that accolade is more appropriate for some of
the firm's more economical VCRs, which offer
limited controls in keeping with the user's
potential needs.
Two-stage evaluation
I decided to evaluate the VS-G2100 VCR in
two stages. The first stage involved a
laboratory evaluation of its electro-acoustic
performance. That was followed by a subjec¬
tive evaluation of its video characteristics,
using pre-recorded tapes and special
demonstration software. The laboratory assess¬
ment of the VCR's audio characteristics was
interesting, and it provided an insight into just
how good the latest generation of VCRs with
digital audio channels have become.
The advantage of a two-speed VCR is that
when used in the 'standard play' (SP) mode,
the recorder should provide an almost flat fre¬
quency response from 20Hz to 20kHz, sup¬
plemented by optimum video performance.
When switched to operate in the 'long play'
(LP) mode, a modest reduction in the overall
frequency bandwidth and some reduction in
total dynamic range must be anticipated. The
magnitude of that reduction is primarily deter¬
mined by the quality of the design, and in ef¬
fect constitutes a means of assessing the
quality of the VCR.
As I soon discovered, the VS-G2100
provides outstanding audio frequency
RECORD/REPLAY performance in the SP
mode. The frequency response is just over IdB
down at 20Hz, and is only 0.3dB high at
20kHz. The flatness and overall smoothness of
the performance is exemplary, and both chan¬
nels display the same characteristics.
My evaluation of the overall linearity of the
audio record to replay characteristics, follow¬
ing the latest procedure specified by DIN
45657, reveals a response that is exemplary all
the way down to -71dB. Following that
demanding test, I was not surprised to find
that in the SP mode, the recorder provides an
A-weighted signal to noise ratio of 77dB(A)
relative to +6VU. In like manner, the distortion
ELECTRONICS Australia, June 1995
9
On the left is the record to replay audio frequency response of the VS-G2100, in standard play (SP) mode. On the right is
the record to replay response in long play (LP) mode, for comparison. Note the ripples at the low frequency end.
levels at OVU and -20VU are relatively low at
1kHz, but were moderately high at low fre¬
quencies, being 1% at 100Hz and OVU. The
harmonic distortion components at high fre¬
quencies are again particularly low, and at
6.3kHz were below the noise threshold.
In the LP mode the audio channel fre¬
quency response proved to be marginally
flatter and smoother, with a slightly better low
frequency response. The droop at 10Hz
was -2.8dB, whilst at 20Hz it was -0.5dB.
One unexpected characteristic that caught
my eye was the cyclical ripple in the LP
record-to-replay response curve. The ripple
manifests itself as a series of cycles, each of
which occurs at increments of 50Hz. The peak
to null ratio of the ripple is not high, being
less than 0.2dB overall at -10VU, but that rip¬
ple is indicative of a slightly higher level of
mains hum leakage being recorded and
replayed in the LP mode.
What really surprised me was the overall
bandwidth provided by the LP mode. The high
frequency response rolls down ever so gently,
by 0.4dB between 10kHz and 20kHz. The fre¬
quency response in the LP mode is therefore,
to all intents and purposes, on par with the SP
mode. Whilst the dynamic range is not quite
as good, this VCR provides a very practical
and cost effective means of recording eight
hours of stereo mood music, with digital
quality on a $10 video cassette.
Subjective testing
My evaluation of the video recording char¬
acteristics involved a series of subjective as¬
sessments of the recorder with pre-recorded
material. The first demonstration tape that I
used was a recent pre-recorded hi-fi VHS
video, entitled Vladimir Horowitz — A
Reminiscence. This video runs for almost two
hours, and is an outstanding anthology of a
musician's life. The VS-G2100 provided ex¬
emplary playback of this Sony Classical video
(SHV 53478), providing some of the most out¬
standing and exciting music with video that I
have had the pleasure to watch. I used a pair
of B&W monitor speakers connected to an
Akai TV set CT-K 2976, and the quality of the
sound was fantastic.
I viewed a second Sony pre-recorded video,
entitled Dvorak in Prague — A Celebration,
with Seiji Ozawa conducting the Boston Sym¬
phony Orchestra, in a program celebrating the
centenary of Dvorak's New World Symphony
premier performance in New York. The
soloists were Yo-Yo Ma, Itzhak Perlman,
Rudolf Firkusni and Frederica von Stade, back¬
ed by the Prague Philharmonic Chorus. The
celebration took place in Smetna Hall in
Prague, and the quality of the music and the
intimacy of the video is one over which I can
wax lyrical.
I conducted A-B comparisons of the perfor¬
mance of the VS-G2100 VCR against my cur¬
rent hi-fi VCR and a two year old 'top of the
line' Akai VCR. As I soon discovered, the
video quality of the VS-G2100 VCR on replay
was significantly better than the two other
VCRs, and the quality of picture was matched
by an equally superb quality of sound.
The picture exhibited less colour smear, and
significantly better detail resolution than the
other two VCRs, and I found that it was both
quick and easy to use. To ensure that I wasn't
judging the outcome on the basis of the
quality of the TV set, I swapped the videos
around to assess the performance with the al¬
ternative monitors. The result was a resound¬
ing first place, and best overall performance
for the VS-G2100. I continued my assessment
to evaluate the performance of the VS-G2100
with its G-Code remote control, and found
that it was easy to use and far more con¬
venient than the current separate G-Code
module that I use with my VCR.
The most obvious advantages of the Akai
VS-G2100's remote control is that the G-Code
information is transmitted directly from the
remote control to the VCR, so that problems of
the type that I have experienced with my cur¬
rent G-Code module (resulting from its being
repositioned or disoriented by my
grandchildren, or visitors) are positively and
simply avoided.
After an extended assessment of the VS-
G2100, I have no qualms in commending this
recorder for any intending purchaser who
seeks 'the ultimate' in flexibility, functionality
and matching technical performance. If how¬
ever your quest is a VCR that is just easy and
simple to use, and you have no real need for
all those 'bells and whistles', then Akai has a
range of good VCRs which are more likely to
suit your needs. The physical dimensions of
the VS-G2100 are 425 x 289 x 104mm and it
weighs 5kg. The quoted RRP is $1099.
For further information on the VS-G2100 or
any of the other VCRs in the Akai range con¬
tact Akai Customer Service, PO Box 11,
Homebush 2140; phone (02) 763 6300. ❖
These plots show the record to replay dynamic linearity of the VS-G2100, measured according to the DIN 45657 standard
As you can see, its extremely good right down to -71 dB.
10
ELECTRONICS Australia, June 1995
you one of the widest choice of capabilities and price ranges in the industry. Choices ranging from
the basic Fluke 12 with auto function V-Chek™ and Continuity Capture™, jro the classic Fluke 77
with Auto Touch Hold* and current measurements.
Fluke 77
The classic
Multimeter
To the advanced Fluke 83 with Min/Max/Average recording,
Frequency, Duty Cycle and Input Alert™. Plus a full
line of quality accessories to extend those
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I
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Fluke 83
Full-featured
Multimeter
in the industry. Make the choice
that gives you the most choices.
FLUKE 12 FLUKE 77 FLUKE 83
The Fluke meters listed above feature DC/AC voltage, resistance,
audible continuity and diode test
Capacitance
measurements
Auto Touch Hold*
Auto Touch HokJOOand
Relative modes
V Chek™ (auto function) Current measurements Current measurements
MirvMax Record with Analog/Digita/ display
Relative Time Stamp
ok to Fluke
Call Philips Test and Measurement on (02) 888 0416
for your nearest Fluke Distributor.
Two-year warranty Three year warranty
Continuity Capture™ Ye*ow holster with Flex
Basic accuacy 0.9% Base accuracy 0.3%
For measurements
to 4800 V-A
Anaiog/Digrtai display
Threeyear warranty
Yellow holster with Flex
Stand™_
Input Alert™_
Capacitance
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Frequency and Duty
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Min/Max/Avg Recording
Basic Accuracy 0.3%
READER INFO NO. 2
ihether you’re doing first-level troubleshooting or component-level diagnosis, Fluke meters otter
Fluke 12
Auto-functlon
Multimeter
UPGRADING YOUR PC
WITH A 'MULTIMEDIA' KIT
Nowadays it has become almost essential for a PC to be fitted with a CD-ROM drive and a sound
card. Luckily you can now also add these facilities to an existing computer at relatively low cost,
thanks to the good deals being offered on ‘multimedia’ upgrade kits. Here’s the information you’ll
need to perform this kind of upgrade, using as an example a representative kit from Rod Irving
Electronics: the KTX DS-16.
by JIM ROWE
About two years ago, I upgraded my
home PC by fitting it with a CD-ROM
drive and a sound card. At the time, this
upgrade cost around $1()(X) — partly be¬
cause the double speed CD-ROM drive I
wanted needed a SCSI interface, and that
involved getting a SCSI adaptor card
along with the sound card. It was all fair¬
ly complicated to install, as well.
Things have changed quite a bit, since
then. For less than half the figure I paid
in 1993, you can nowadays get a
‘multimedia’ upgrade kit complete with
double speed CD-ROM drive using the
IDE (integrated device electronics) inter¬
face, a sound card, a pair of small
speakers and some very useful ‘big
name’ bundled software on CD-ROM
discs. Without the bundled big name
software, you can get the hardware alone
for less than $400, while an IDE double
speed CD-ROM drive by itself can cost
as little as $200.
Mind you, things are still changing,
and prices are still falling. By the time
you read this review, the prices of quad
speed CD-ROM drives are likely to have
fallen to the $500 mark or less, and
upgrade kits including them may be
replacing those like the one we’re dis¬
cussing here. The first hex speed drives
have just started to appear, and although
these will no doubt be fairly expensive
for a while yet, they’ll no doubt become
more attractive in time.
(By the way, ‘double speed’ simply
means that when the drive is reading a
CD-ROM disc, it spins it at twice the
speed of a normal audio CD. This means
that the data can be read from a disc at
twice the original speed, or 300KB per
second instead of the 150KB/s of the
first ‘single speed’ drives. The newer
‘quad speed’ drives double the speed and
transfer rate yet again, to 600KB/s, while
the very latest ‘hex speed’ drives reach
900KB/s. These rates are for continuous
or sustained data transfer; most drives
can achieve faster rates for short bursts
of data.)
Even though the particular upgrade kit
we’re using as an example in this article
may be technically ‘obsolete’ quite soon,
then, we thought it might be worthwhile
to use it to present a kind of snapshot of
the current situation, regarding
‘multimedia’ upgrades. Hopefully if
nothing else it will give you an idea of
what to expect, if you decide to upgrade
your own PC in this way.
The upgrade kit we’re going to discuss
came from Rod Irving Electronics, and is
apparently used in some of RIE’s own
complete multimedia computers, as well
as being sold separately. It includes the
following items:
1. A double speed ‘internal’ CD-ROM
drive, which fits in a standard half¬
height 5.25" floppy drive bay, and uses
the IDE interface.
2. A 16-bit stereo sound card, fully com¬
patible with the de facto standard estab¬
lished by the Adlib, Sound Blaster and
Sound Blaster Pro cards.
3. The necessary cables, manuals and in¬
stallation software for both Windows
and DOS.
4. A pair of small ‘outboard’ speakers, to
hook up to the sound card’s inbuilt
stereo amplifier.
5. A bundle of applications software on
CD-ROMs, consisting of the following
packages:
• Microsoft’s Encarta ’95, the extreme¬
ly popular interactive multimedia en¬
cyclopedia.
• Microsoft’s Works for Windows , the
popular suite of office software which
includes a word processor, spread¬
sheet with charting, database with
reporting, communications program
and drawing program.
• Microsoft’s Money , the personal
finance management program.
• A fourth CD-ROM called ‘CD Deluxe
Pack 4’, which provides Chessmaster
4000 Turbo , Mavis Beacon Teaches
Typing V2.0 , The Software Toolworks
US Atlas V4.0 and The Software Tool¬
works World Atlas V4.0.
And at the time of writing, the price
for this complete package is only
$449.00 — surely excellent value for
money, considering that the three
Microsoft packages alone would probab¬
ly cost close to this amount, if they were
purchased separately.
The CD-ROM drive
Let’s take a closer look at the two
main hardware items, the CD-ROM
drive and the sound card, before we look
at what’s involved in fitting them into a
typical PC.
The latest breed of CD-ROM drives
are designed to connect into a PC using
an enhanced version of the same IDE in¬
terface used for most hard disk drives,
known as the ATAPI interface (see data
panel). With the IDE/ATAPI system, the
drive’s ‘controller’ is built right into the
drive itself, and communicates directly
with the computer’s CPU.
The drive electronics are effectively
allocated to a ‘port’ in the computer’s
I/O memory space, just like a printer or
serial communications port. And in the
same way, data flows between the drive
controller and the CPU via a similar se¬
quence of interrupt requests (IRQ’s),
programmed bus transfers and direct
memory access (DMA) channel trans¬
fers. So with the IDE system, a CD-
ROM drive is allocated a specific I/O
address, IRQ line and DMA channel —
just like a hard disk or serial port
adapter card.
This means that if you have only a
single IDE hard disk, like most people,
this type of CD-ROM drive can be con¬
nected to the same IDE port on your
mother board or ‘paddle’ card, as the
secondary or ‘slave’ drive (the HDD be¬
comes the primary or ‘master’). How-
12
ELECTRONICS Australia, June 1995
Along with the main items shown here, the RIE kit includes further software and all necessary cables.
ever since many of the modem sound
cards also provide a second IDE port,
specifically for a CD-ROM drive, it’s
just as easy to use this if it’s available.
Often this approach is also more
straightforward.
Physically an ‘internal’ CD-ROM
drive is almost identical in size to a
standard ‘half height’ 5.25 M floppy disk
drive, and mounts into the computer in
the same way.
It runs from +12V and +5V obtained
from the PC’s power supply, using one
of the same four-way power leads used
by the hard and floppy disk drives. A 40-
way ribbon lead connects it to the IDE
port connector, and a small four-way
audio lead connects it to the mixer/
amplifier on the sound card for playing
audio discs.
The CD-ROM drive supplied in RIE’s
KTX DS-16 kit has a motor-driven tray
assembly like most modern audio
players, and doesn’t need each disc to be
fitted into a protective ‘caddy’. On the
front panel it provides a ‘tray open/close’
button, an ‘audio play/skip track’ button,
an earphone jack and volume control for
listening to audio CDs, and a green LED
which indicates disc reading activity.
When open for loading or unloading, the
disc tray can also be closed by giving it a
small push inwards.
The sound card
Turning our attention now to the sound
card, you’re probably aware that most of
today’s sound cards combine a number
of essentially separate functional blocks:
• A digital audio ‘codec’ (coder/
decoder), able to perform A-D and D-
A conversion of audio signals
(generally in stereo), at a variety of
sampling rates. Quite often it can also
perform compression and decompres¬
sion of the digitised audio, for smaller
file sizes and efficient file transfer.
• A music synthesiser, able to produce
stereo simulations of a variety of
musical instruments in response to
MIDI (Musical Instrument Digital In¬
terface) commands.
• A joystick/external MIDI port, for
connecting an external joystick for
playing games, and/or a MIDI
breakout box for linking the computer
to an external MIDI synthesiser, key¬
board and other instruments.
• A small stereo audio amplifier, typi¬
cally with an output of 2W per chan¬
nel, and capable of driving a pair of
external speakers. Often a software-
driven mixer and volume control is
built into the amplifier, allowing con¬
venient setting of the volume from the
digitised audio D-A, music synthesiser
or CD-ROM player when playing an
audio disc.
• In most cases, a ‘secondary’ IDE in¬
terface port, intended to service the
CD-ROM drive.
As you can see, there are quite a few
distinct subsections of a sound card, and
a number of them need their own I/O
port address, and possibly their own IRQ
line and DMA channel setting so that the
CPU can communicate with them
without confusion.
This applies to the audio codec, the
music synthesiser, the joystick/extemal
MIDI port and the IDE/ATAPI port for
the CD-ROM drive. That’s why sound
cards traditionally end up with quite a
few header pin strips and jumpers, and
why setting them up to work correctly in
a particular computer can often be a bit
of a nightmare.
In fact, it was probably sound cards
that someone had in mind, when they
coined the somewhat ironic phrase ‘Plug
and Pray’, to describe the current situa¬
tion when you’re adding cards and
peripherals to a PC. The recently
proposed ‘Plug and Play’ standard is in¬
tended to solve these sorts of problem...
The ‘SP300’ sound card in RIE’s KTX
DS-16 kit is a half-length card which
provides virtually all of the above func¬
tions. The audio codec handles 8-bit or
16-bit sampling of stereo signals, at rates
up to 44.1kHz — which makes it
nominally capable of making CD-quality
recordings. It can also perform either
ADPCM or ESPCM compression and
decompression, in the process.
The music synthesiser section is based
on a Yamaha OPL3 FM synthesiser chip,
which uses four-operator FM synthesis
to produce 20-voice stereo instrument
synthesis, in a way that is fully com¬
patible with the Sound Blaster Pro. The
card is also designed to take an optional
SP260 ‘daughter card’ which provides
PCM ‘wavetable’ synthesis, to upgrade
the synthesiser performance. From the
manual it appears that when the daughter
card is fitted it takes over the I/O ad¬
dress, IRQ and DMA used for the joy¬
stick/extemal MIDI port.
The manual doesn’t specify the output
capability of the card’s inbuilt audio
amplifier, but from the chip used it is
probably able to produce about 1.5 - 2W
per channel.
It can produce quite a respectable
volume from the tiny speakers supplied
with the kit, and even more from larger
and more efficient speakers.
The card’s software-programmed
audio mixer has the ability to combine
and adjust the levels from six stereo and
one mono source.
Its rear mounting bracket provides the
usual array of connectors: line audio and
mic audio inputs, line audio and speaker
ELECTRONICS Australia, June 1995
13
UPGRADING YOUR PC WITH A MULTIMEDIA ’KIT
outputs, and of course the 15-pin DB
connector for the joystick/extemal
MIDI port.
On the card itself there’s the 40-way
connector for the CD-ROM drive
IDE/ATAPI digital cable, a four-way
connector for the audio from the same
drive, a couple of DIL pinstrips to mate
with the optional SP260 daughter board,
and — inevitably! — a number of
header strips with jumpers to set the
various I/O address, IRQ line and DMA
channel options.
Fitting the hardware
Having looked at the CD-ROM drive
and sound card as pieces of hardware,
then, let’s now see how easy or other¬
wise it is to fit them into the PC.
In the sheer physical sense this is
generally not a problem; the CD-ROM
drive simply slides into a spare floppy
drive bay, and is mounted using the
usual pair of screws on each side.
You’ll probably need to remove the
‘blanking plate’ from the front of the
computer case, to allow access to the
front of the drive, but apart from that
there’slittle else to do except connect the
IDE/ATAPI cable and audio cable to the
rear, along with one of the computer’s
drive power leads.
Similarly the actual fitting of the sound
card is fairly straightforward, as it’s a
half-length ‘16 bit’ type and most
machines will have a suitable spare
slot. About the only possible complica¬
tion is where your machine is of the
Tow profile’ type with the plug-in
cards mounted horizontally — like the
one we tried out the RIE kit in. We had
to do a bit of card swapping, in fact, be¬
cause the ‘tang’ of the sound card’s
mounting bracket initially clashed with a
connector on the tang of the card on the
opposite slot...
But the tricky part of the operation ac¬
tually comes before you fit the sound
card. You guessed it — this is the part
where you have to set jumpers for the
various I/O address, IRQ line and DMA
channel settings, to ensure that the CPU
can communicate with everything
without coming to grief. This is the stage
where even the experts tend to cross at
least one pair of fingers, and not relax
fully (or screw the computer’s case back
on) until they’ve fired it all up and run a
few diagnostic tests.
Surely there are a few basic rules to
guide you, in setting up these jumpers?
Of course, and in a minute we’ll give
you a brief rundown.
Just remember, though, that this is
the area where there aren’t any guaran¬
tees; even following all the rules
doesn’t ensure that you won’t strike
trouble, in a particular machine with its
particular combination of processor,
motherboard, BIOS and plug-in cards. It
just gives you a much higher probability
of success.
The I/O address
First of all, let’s consider the matter of
THE IDE/ATAPI INTERFACE
We are grateful to Gary Kicic, chief technician at Rod Irving
Electronics, for the following summary of the technical details
of the IDE/ATAPI interface and its development:
The dominant hard disk interface in the personal computer
market since early 1991 has become the Integrated Device
Electronics (IDE) or ‘AT-Attachment’ type. With an IDE/ATA interface
the hard disk drive has all of the necessary control electronics built
into it, removing the need for a separate and dedicated controller
card to interface the computer’s expansion bus to the hard disk (as
is required in the ST506, ESDI and SCSI interface standards).
The drive itself, not the cable, determines what drive letter is as¬
signed to it.
The IDE interface does not aim for full plug compatibility with the
ISA bus. The drive is interfaced through a 40-pin cable, connecting
to the bus either via a ‘paddle card’ or directly to the mother board.
The only function of the paddle card or mother board IDE port is to
present only those signals required by the drive — and more impor¬
tantly, provide buffering. It is not a device controller.
The original IDE specification, which was approved in 1991 by the
CAM (Common Access Method) committee, allowed for two physi¬
cal drives to be attached to one paddle card. All signals from the
card were extended to both drives, and jumpering on the drives
determined the actions of each. The jumpering set each drive as a
‘master’ or slave’, however the master drive is master in name only.
It does not control the slave drive in any way, other than to provide
the address decoding for both drives in a two-drive system.
All IDE drives can be configured as either a master or a slave. Most
are shipped jumpered as a master drive, although some have a
neutral jumper position that allows the drive to operate correctly in a
single drive system.
The idea of a using a single paddle card to interface two IDE drives
was soon extended, to cover the introduction of a second paddle
card — to allow up to four drives to be attached to the ISA bus. The
second paddle card required a BIOS extension ROM to be fitted so
that the PC can recognise more than two drives.
This then resulted in the following IDE options:
Primary IDE paddle port
Master: Physical drive 1
Slave: Physical drive 2
Secondary IDE paddle port
Master: Physical drive 3
Slave: Physical drive 4
When CD-ROM drives began to be fitted, until recently most of
them used either the SCSI (Small Computer Systems Interface) or
a proprietary interface. This required yet another interface standard
— or in some cases a non-standard one.
With the ever-increasing pressure to reduce the total systems cost,
it was inevitable that the question was soon asked: If the IDE inter¬
face will handle two drives, and the majority of personal computers
only require one hard disk, why can’t we interface the CD-ROM
drive using the same interface?
It did not take long to provide a solution. An IDE hard disk is re¬
quired to read and write chunks of data; the job of a CD-ROM drive
is even simpler — it is only required to read data, and sometimes
audio instead. The audio is taken care of by a separate two-chan¬
nel audio connector, but control of the data functions of a CD-ROM
drive was another matter.
The solution was to come from another committee, the Small Sys¬
tems Form Factor Committee — in the guise of the ATA Packet In¬
terface or ‘ATAPI’ standard. The ATAPI was designed to be
completely compatible with existing ATA (IDE) hardware and
drivers; it changes nothing on the processor side of the AT connec¬
tion and does not affect the operation of IDE drives. Its correct im¬
plementation simply provides manufacturers and programmers with
a path to link CD-ROM drives to PCs in a standard way.
Under ATAPI, a CD-ROM drive can replace the slave IDE hard
drive in a PC, provided that the hard drive is configured as the
master. A CD-ROM drive must however be configurable as either a
master or slave, to allow a two CD-ROM system. They are normally
shipped configured as a slave.
The ATAPI standard also extended the number of commands re¬
quired for command and control of ATA devices. This was required
for the ‘packet’ nature of data transfer required by the CD-ROM.
Of course nothing stands still, in the modern computer market. The
ATA interface standard has just recently been upgraded to include
ATA-2 specifications. In brief this allows for drive capacities of more
than 528MB (megabytes) and caters for the higher data transfer
rates currently being introduced. Programmed I/O transfer rates up
to 11.5MB/S are readily obtainable under ATA-2.
The ATA-2 specification also caters for the IDE paddle card or port
having four disks or devices attached. However there is still a re¬
quirement for two physical cables, connected to the primary and
secondary ports of the interface card.
I believe ATA-3 is currently in the pipeline, with transfer rates of up
to 20MB/s and a change to the hardware interface. We live in inter¬
esting times!
14
ELECTRONICS Australia, June 1995
I/O addresses. As you can see from Table
1, quite a few of the modem PC’s range
of I/O memory addresses are already al¬
located to various parts of the system, or
‘reserved’ for standard add-ons such as
serial port adaptors, printer ports, etc.
However there are some spare addresses
available, for things like sound cards and
their various functional sub-sections:
note the ‘gaps’ from 0E0 to OEF, from
100-167, from 208-277, from 280-2AF,
from 320-35F and so on.
In principle, then, the idea is to set the
I/O address links on your sound card so
that its codec, synthesiser, etc., are given
addresses in one of these ‘free’ areas, so
there won’t be any conflicts or confusion
when the CPU tries to communicate with
or control them. (Generally the link op¬
tions are labelled in terms of the
different ‘base address’ settings,
where the base address is the
lowest of the small range of ad¬
dresses needed.)
This may sound simple enough,
but it often isn’t quite that easy...
For example many sound cards
don’t give you a huge range of
choices, when it comes to choos¬
ing the I/O addresses. You often
only have two, three or perhaps
four at most to choose from, and
some of these may be for addres¬
ses that are already ‘spoken for’
in your computer.
Another, more subtle problem
is that some plug-in cards (in¬
cluding some sound cards!) don’t
fully decode their I/O address, so
that as well as occupying their
‘official’ address range they may
quietly also occupy others. This
means that some of the ‘free
areas’ in I/O space may not be
free at all, and trying to position
your sound card’s codec or syn¬
thesiser there may still produce
unexpected problems.
In general, all you can do is try
to match one of the address options
that your sound card does provide,
with a free I/O area in your PC, and give
it a try. Then if problems occur, you try
another one — until everything seems to
work correctly.
Actually there’s another consideration
as well, and one that can often help you
in making the choice. While Windows-
based software can generally cope with
almost any range of I/O addresses for
your sound card sub-systems, a lot of
DOS-based software like games simply
assumes that you’re using a Sound
Blaster or SB-clone card, and that it’s at
the ‘default’ base addresses used by
Sound Blaster: 220 hex for the codec,
and 330H for the external MIDI port. So
if your sound card jumpers are able to be
set for these I/O address options, they
can be an excellent place to start. Quite
often they seem to work well, anyway.
IRQ selection
Now we come to the setting for the in¬
terrupt-request or ‘IRQ’ lines needed by
the sound card sub-systems. Each sub¬
system needs to be allocated its own IRQ
line, so that it can indicate to the CPU
when it is in need of ‘urgent attention’.
As you can see from Table 2, many of
a modem PC’s complement of IRQ lines
are also already used by existing ports or
controllers, or reserved for them. On the
surface that makes it appear that only
IRQ’s 10, 11, 12 and 15 are likely to be
free for use by your sound card sub-sys¬
tems. However things are quite often a
little more flexible than this.
For example, although IRQ’s 7 and 5
are officially allocated to the first and
second printer ports respectively, modem
printer ports generally use programmed
I/O and don’t actually use interrupts. So
both these lines may well be free, even
in computers where there are two printer
ports and they’re in use. Certainly where
there’s only only printer port, and no
more than two serial ports, it’s very like¬
ly that IRQ5 will be free.
This is why the usual ‘default’ setting
for the Sound Blaster cards is IRQ5, and
again this is generally the best place to
start, assuming your own sound card
provides this option. If for some reason
IRQ5 doesn’t give correct operation (not
very likely), you can generally try
IRQ10.il or 7.
DMA channel...
Finally, there’s the matter of choos¬
ing the correct DMA (direct memory
access) ‘channel’ for your sound card.
Generally each of the computer’s
‘intelligent’ peripheral sub-system con¬
trollers has to be allocated one of the
eight DMA channels, so that it can or¬
ganise its own high-speed transfers of
data to and from memory, via the main
address and data busses. They don’t al¬
ways have to be allocated a chan¬
nel on a totally ‘exclusive’ basis,
but devices which could con¬
ceivably want to use the busses at
the same time must be allocated
different channels, to prevent
clashes.
Table 3 shows the usual DMA
channel allocations in a modem
‘AT’ type machine. The main chan¬
nel ‘spoken for’ is channel 2,
which is always used by the floppy
disk controller and is best left for
its exclusive use. Although channel
0 is used for refreshing the DRAM
memory in XT type machines, it
isn’t used for this purpose in AT
machines, and can often be used.
As before, if your sound card
gives various DMA channel op¬
tions, the idea is to choose one
which isn’t likely to conflict with
any other device controller. The
DMA settings for the 16-bit Sound
Blasters are channel 1 for 8-bit
transfers and channel 5 for 16- bit
transfers, and one or other of these
is usually a good place to start.
RIE’s sound card
The SP300 sound card in RIE’s
upgrade kit had jumpers allowing
it to be set up for the de facto Sound
Blaster standard settings of I/O base ad¬
dress 220H, IRQ5 and DMA channel 1.
(In fact it came with default settings very
close to this — we only had to change
the IRQ jumper, which was set on
IRQ7.) So we used these settings, and
they turned out to be fine for the
486/66MHz computer in which we in¬
stalled the kit.
The card also had an enable/disable
jumper for the on-board CD-ROM drive
IDE/ATAPI port, which was already set
to ‘enable’ so we left it that way. The
port appeared to be fixed at the ‘IDE/
Table 1:
I/O Address assignments (AT)
Address
Used by
(hex)
000-01F
DMA controller 1
020-23F
Interrupt controller 1
040-05F
Timer
060-06F
Keyboard/Mouse controller
070-07F
Real-time clock, NMI mask register
080-09F
DMA page register (80 = POST code port)
0A0-0BF
Interrupt controller 2
0C0-0DF
DMA controller 2
0F0-0FF
Maths coprocessor
168-16F
IDE/ATAPI port 4
170-177
IDE/ATAPI port 2
1E8-1EF
IDE/ATAPI port 3
1F0-1F8
Hard disk (IDE/ATAPI port 1)
200-207
Game I/O (Joystick/MIDI)
278-27F
Printer port LPT2: (LPT3:)
2B0-2DF
EGA/VGA video adaptor (alternate)
2E1-2E3
Data Acq/GPIB Adaptor 0
2E8-2EF
Serial port COM4:
2F8-2FF
Serial port COM2:
300-31F
Prototyping card
360-36F
Network adaptor
378-37F
Printer port LPT1:(LPT2:)
380-38F
SDLC/Bisync adaptor 2
3A0-3AF
Bisync adaptor 1
3B0-3BF
MDA video adaptor, printer port (LPT1:)
3C0-3CF
EGA/VGA video adaptor
3D0-3DF
CGA video adaptor
3E8-3EF
Serial port COM3:
3F0-3F7
Floppy disk controller
ELECTRONICS Australia, June 1995
15
UPGRADING YOUR PC WITH A ‘MULTIMEDIA’ KIT
ATAPI port 2’ base address of 170H,
with IRQ15 for its interrupts, and this
didn’t clash with anything else.
Another juniper was identified as 'CD-
ROM I/O Channel Ready’, but was set
by default to the ‘disabled’. The exact
purpose of this jumper is a little vague; it
seems to be used by slow CD-ROM
drives to introduce additional wait states
for the CPU, if they can’t keep up. We
left the jumper in its default position, and
everything turned out fine...
We did have one minor hassle with
three other jumpers on the SP300 card,
however. These were described as select¬
ing either the internal or external MIDI
port, and the manual seemed to indicate
that to use the external port (which we
wanted), they had to be set to the ‘MPU-
401’ positions.
We did this, but later discovered that
this was wrong; the external MIDI port
remained ‘dead’ until we swapped the
jumpers back to their default ‘SB- MIDI’
positions. It wasn’t a major drama, but
things would have been easier if the
manual had been clearer and/or correct.
Software setup
Once you’ve set the sound card’s
jumpers, fitted it into the computer and
attached the cables to the CD-ROM
drive, the final step is to install and setup
up the matching software. This is
generally done in two stages: installing
the ‘driver’ routines so that DOS, Win¬
dows and their applications programs are
able to locate and communicate with the
sound card and CD-ROM drive, and
then installing any applications software
that may come with the sound card —
music player programs, and so on.
With the R1E upgrade kit there were
three floppy disks in all — two with
drivers and applications for the sound
card, and one with the driver for the CD-
ROM drive. The sound card software
came with its own INSTALL.EXE pro¬
gram, while the CD-ROM driver had its
own SETUP.EXE program. Both install¬
ing programs ran under DOS.
We struck a couple of minor hassles
during the installation, as it happens. Ini¬
tially INSTALL.EXE ground to a halt,
proclaiming that it couldn’t copy a
file called THREED.VBX to the hard
disk. It turned out that because our
machine had Windows for Workgroups
3.11 installed, the file concerned was al¬
ready on the hard disk, and IN¬
STALL.EXE didn’t seem to know how
to cope with this eventuality...
We solved this one by renaming the
existing THREED.VBX, and trying
Table 2
Basic IRQ assignments
(AT)
IRQ line Assigned device
IRQO
System Timer
IRQ1
Keyboard
IRQ2
(Used by controller for IRQ8-15)
IRQ3
Serial port COM2: or COM4:
IRQ4
Serial port COM1: or COM3:
IRQ5
(Printer port LPT2: or LPT3:)
IRQ6
Floppy disk controller
IRQ7
(Printer port LPT1: or LPT2:)
IRQ8
Real time clock
IRQ9
BIOS
IRQ10
(Network adaptor)
IRQ11
(Available)
IRQ12
(Available)
IRQ13
Maths co-processor
IRQ14
Hard disk controller
IRQ15
(Available)
again. This time INSTALL.EXE was
happy, and installed all of the sound card
software with no further problems. We
checked later to determine the version of
THREED.VBX with the later date, and
this was the version we elected to use.
The other hassle was with the CD-
ROM software driver installer
SETUP.EXE, which simply wouldn’t
run on our machine — perhaps be¬
cause it was running Novell network
software. Anyway, we found from a
README file on the floppy that all
SETUP.EXE was supposed to do was
copy over the CD-ROM driver (called
VIDE- CDD.SYS) to the hard disk, and
add a line into our CONFIG.SYS file so
that it’s installed into the system during
boot-up:
DEVICE=VIDE-CDD.SY S
/D:MSCD001 /P: 170,15
where the ‘/P:170,15’ switch on the end
is to tell the driver where to find the CD-
ROM drive, at I/O base address 170 and
using IRQ15. So we did these operations
manually, and everything turned out to
be fine.
The end result
When our basic installation was com¬
plete, I tried installing and running a
couple of applications programs to test
Table 3
DMA channel usage
Channel 0 DRAM memory refresh (XT)
Channel 1 (Available - 8 bit)
Channel 2 Floppy disk controller
Channel 3 (Available - 8 bit)
Channel 4 First DMA controller
Channel 5 (Available - 16 bit)
Channel 6 (Available - 16 bit)
Chan nel 7 (Ava i lab l e - 16 bit)__
the computer’s newly acquired multi-
media capabilities (and also make sure
that there weren’t any clashes).
One package was the very nice MIDI
Music Sequencer package Powertracks
Pro , which I’ve found to work very
well with my Kawai G-Mega syn¬
thesiser module, connected via the
MIDI Breakout Box I described in the
February 1994 issue. This was when I
discovered the problem noted earlier,
where the external MIDI port wouldn’t
work with the sound card jumper set¬
tings given in the manual. Swinging
the jumpers back solved this one,
though, and Powertracks Pro happily
played MIDI files out through the
Kawai G-Mega, and accepted input
from a MIDI keyboard.
On the advice of RIE’s chief tech¬
nician Gary Kicic VK3TOV, who is
very experienced in the business of
building up and debugging modern PC
systems, I also tried installing and run¬
ning Microsoft’s Encarta 95, directly
from one of the CD-ROMs supplied in
the kit. Gary tells me that Encarta is a
very good benchmark, because if your
system has any subtle clashes it either
won’t install, or won’t run correctly.
As it happens, Encarta 95 both in¬
stalled and ran on the system without
any problems.
So after trying it out for a while (it’s a
most impressive package!), I was able fit
the cover back on the computer, and
pronounce its upgrade ‘operation’ as
complete. As you can see, although in¬
stalling one of the current ‘multimedia
upgrade’ kits is somewhat easier and
less problematic than it has been in the
past, there can still be a few minor
complications. It pays to have a
reasonably clear understanding of what
you’re doing, as this will allow you to
sort out any of these complications
when they occur.
Hopefully the information given in
this article will help you you carry
out this job with a high probability
of success.
My grateful thanks to Gary Kicic of
Rod Irving Electronics for his assistance
in preparing the article, and also to Rod
Irving himself for suggesting that an ar¬
ticle along these lines would be a good
idea, and prompting me to do it by send¬
ing a typical kit.
Needless to say, if you’ve been en¬
couraged by the article to ‘give it a go’
and upgrade your own computer, you’ll
find a range of suitable kits in RIE’s
stores. You’ll find the addresses in their
advertisements. ❖
16
ELECTRONICS Australia, June 1995
ELECTRONICS AUSTRALIA'S
READER INFORMATION SERVICE
COMPUTER BULLETIN BOARD
As part of its service to readers, Electronics Australia operates a Reader
Information Service Bulletin Board System (BBS). This makes available
a wide range of useful information, for convenient access and rapid
downloading by readers with a personal computer and modem (we
know that many readers have these facilities, nowadays).
Here’s an idea of what’s currently available on the BBS:
• Software needed for recent PC-based EA construction projects
• Project index files for EA and ETI construction projects
• Recent notes and errata
• Useful pOblic domain and ‘shareware’ software for electronics and
amateur radio applications
• General interest shareware utilities, such as the compression and
decompression utilities used for faster file transfer.
The Electronics Australia Reader Information Service BBS is ANSI-
compatible and is currently operational for virtually 24 hours each day,
seven days a week, on (02) 353 0627. Your modem can be set to any
standard speed from 300 to 28,800b/s full duplex, with a data format of
‘8-N-1 ’ (eight data bits, no parity and one stop bit).
We re planning to increase the range of facilities available on the BBS
soon, by adding such things as a discussion forum and a more conven¬
ient way for readers to send us ‘Letters to the Editor’ and contributions
to columns like Forum and Information Centre...
So call up the Electronics Australia BBS and take advantage of its
facilities — there is no cost for accessing the system itself, which is
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usual cost for a phone call.
Note that for those readers without a modem, we can still supply project
software and/or index files for $5.00 if you send us a formatted high
density 3.5" or 5.25" floppy disk.
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ELECTRONICS
a ^ 1
with NICK de VRIES miame, amsae, fi Diag e
Using a scope for vehicle faultfinding — 2
In mv last column we started to look at the use of a lab scope in an automotive capacity, and this
month we will explore this concept further. I am including some prints of waveshapes captured wit
a digital scope, to make things clearer. (Funny how the digital scope comes in so handy to illustrate
an analog waveform!)
Carrying on with my theme of ‘input
signals’, it seems (themes?) to be a
good idea to mention a few of the
more common waveshapes that the
automotive technician has to be
familiar with. Having promised to
show you ‘how to make sense of the
squiggly lines’, Fig.l is a breakdown
of the ‘coil negative’ signal for a tradi¬
tional Kettering system, highlighting
the segments of interest.
To include a view of even the more
well-known faults that afflict the Ketter¬
ing system would take several pages
of illustrations and explanations, so I
hope you will manage for now with just
knowing what a good signal looks like.
With new developments in igni¬
tion coil design and manufacture,
the coil negative or ‘primary’
waveshape has changed some of its
basiccharacteristics.
Notably, the ‘ringing’ effect or oscilla¬
tions have all but disappeared. Fig.2
shows, at 20 volts per division, the
waveshape of a Ford EB fitted with a
‘Transformer’ coil (they were always
transformers, but it sounds like a trendy
name!); as you can see, aside from the
different trigger point, there are sig¬
nificant differences from the waveshape
in Fig.l.
Coil positive wave
Those of you who have had some
training in electronics may recognise the
characteristic inductor charge-up
waveform displayed in Fig.3, taken
from the coil positive terminal. Only
contact-breaker type ignition systems
fitted with a ballast resistor in series
with the coil will have this type of wave
— all other systems have the coil
strapped to battery positive through the
ignition switch.
If you are using a dual-trace scope
on this and the coil negative signal,
try triggering the sweep off the rising
edge of either input in ‘chopped’ mode,
to observe the timing relationship of the
two signals.
The instant just before the coil is
fired is the point where maximum cur¬
rent is drawn; to test for voltage
drop in the switching circuit, measure
the height above ground of the coil
negative trace at this point, it should be
no more than 0.3V.
Electronic ignitions have a variety of
waveshapes, depending on the type of
Fio 1 (left) : The coil negative'signal of a traditional Kettering ignition system, with features of interest identified. A is where
the points are opening, look for hash or arcing; at B are the primary coil oscillations, gradually decreasing over
approximately 1.5ms; at C are the coil/condenser oscillations, where the coil energy dissipates down to system voltage,
and finally D is where the points close again. This should be a dean switch down to ground. Fig.2 (right): Decades after Dr
Kettering we see here a very clean and hash-free primary ignition signal from Mr Ford. In fact, it 's an EB Falcon six cylinder,
with variable current control instead of a ballast resistor and thick film transistors instead of contact breakers.
20
ELECTRONICS Australia. June 1995
current limiting used and the voltage at
this same point will vary from 0.6 volts
(one transistor) to about 9.6V with cur¬
rent limiting.
Purpose-built automotive scopes
sometimes make this measurement for
you and display a digital value of the
reading just to make things easy; but as
we are doing this with a general purpose
scope, we’ll have to persevere doing
things manually.
Another common although little un¬
derstood signal (from a testing point
of view) is the oxygen sensor output.
In the March edition of EA I included
a snapshot of an oxygen sensor output
signal, when the throttle was being os¬
cillated between closed and about 50%
open as rapidly as possible to observe
the full scale transition and speed of
the sensor.
In the interests of saving space, trees
and ink. I’ll leave the illustration out
this time; however, the principle here is
that the voltage ranges between zero
and one volt depending on fuel mixture
strength, and it also does it in a
reasonably rapid manner.
The sensor in my VL Commodore
measures about 80ms rise (lean to rich)
and 40ms fall (rich to lean). A sensor
that is ‘dying’ might take 150ms to fall
from maximum rich to lean, which is
much too slow when you consider how
fast things are happening in the combus¬
tion chambers.
Knock sensor
On to another rare gem from the
blurred category I alluded to in April’s
column under ‘input signals’. Fig.4
shows the output of the knock sensor,
caught in the act of ‘hearing’ a severe
knocking or detonation in an over-ad¬
vanced ignition timing condition. This is
the familiar ‘marbles in the cylinders’
sound, often heard when inattentive
drivers forget to change down a gear to
drive around a comer.
The promise of technology in this ap¬
plication is that, providing the sensor is
placed in the appropriate spot in the en¬
gine block, the signal is sent to the ECU
at the onset of engine knock.
The ECU responds by retarding the
ignition timing (or firing point of
the next ignition cycle) by about
two or three degrees, and gradually
restores the full advance over a period
of engine cycles.
If the engine is of a quiet enough
design, with well-damped cam chains
and hydraulic rocker arms, the ECU
can be tuned to only retard the
firing point on the offending
cylinder, rather than a blanket ‘all
cylinders’ approach. Some engine
designs use this function, but I suspect
that it is somewhat difficult to achieve
with any sort of reliability in an over¬
head camshaft engine.
I believe some of the more exotic of¬
ferings from Europe have one knock
sensor per cylinder, in an attempt to pro¬
vide the maximum amount of advance
possible for each cylinder and therefore
not sacrifice too much power when fuel
quality — for example — is not quite up
to scratch.
At an Adelaide SAE meeting in
February this year, guest speaker Ken
Stanford, an engineer with Ford Motor
Co., gave us an interesting snippet about
knock sensor operation.
In the new EF series six cylinder en¬
gine, to eliminate any confusion in the
ECU, it only ‘listens’ to the knock sen¬
sor when it is approaching the correct
phase of the engine’s ignition cycles.
This blocks out any unwanted goings on
at a similar frequency (7kHz), to
prevent them from influencing the ECU
unnecessarily.
Variable voltages
Now it’s time to look at some signals
from the ‘Category Two’ variable volt¬
age group. This group contains only
analog signals, with no timing implica¬
tions whatsoever.
Fig.5 is the output from an air mass
meter, with the engine accelerating from
idle to high speed over a period of about
900ms. The initial surge is used by the
ECU to calculate acceleration enrich¬
ment, similar to the accelerator pump in
carburettors. Although the signal drops
back to just above the idle value, the en¬
gine speed takes quite a bit longer to
return to idle.
It would be nice to show you the ac¬
celeration and deceleration curves su¬
perimposed on this picture, but I don’t
have a tacho with a suitable analog
output to use as a ‘B’ channel input.
Does anyone have a circuit for such a
device?
Here’s a question, regarding the
AMM signal of Fig.5. I haven’t yet
come up with a reason for the oscilla¬
tions in the high speed range, perhaps
someone can enlighten me?
The oscillations in the low speed end
of the curve I’m happy to attribute to
pulsations in the inlet manifold, the
amplitude of which smooths out after
the engine speed increases by about
the 300ms mark, and the in-coming air
stream becomes one continuous draft.
Fig.3(left): The coil positive signal in a ballasted’Kettering system. Your DMM won't show this sort of detail... Fig.4 (right):
Who’s that knocking at my door? A knock sensor in full voice, care of an Audi in need of premium unleaded fuel. Your DMM
definitely won’t show you this, either!
ELECTRONICS Australia, June 1995
21
Fig.5 (left): An air mass meter with a problem ? The engine was accelerating from idle to high speed over about 900ms. Note
the oscillations, dying away and then building again as the engine revs increase. Can anyone explain what causes them?
Fig.6 (right): Is the output from your throttle position switch as clean as this ? This one isn’t quite adjusted correctly, though.
But what’s happening at the peak
revs end?
Drop us a line, or give me a call on
(085) 63 0607. Perhaps you have an
idea what’s going on, or maybe you
would like to see an article devoted to a
particular aspect of Automotive
Electronics in a future edition...
Throttle sensor
An important function to test in EFI
vehicles is the quality of the throttle
position sensor (TPS) signal. There are
three types that I am aware of; the early
‘D’ Jetronic EFI systems employed a
type of grid and wiper switch, to give a
digital signal that indicated both throttle
position and the speed of opening or
closing, Later systems employed a
three-terminal type with idle and full
load contacts built in, leaving the air
flow/mass meter to determine accelera¬
tion enrichment.
The current crop of motor vehicles
tend to use the variable resistor variety
of throttle sensor, which must be set to a
particular voltage at idle by means of an
adjustable slotted clamping bracket.
From this sensor the ECU determines
idle position, how fast the throttle is
opened (‘struth, he’s floored it!’), and
the position at all times.
Most drivers use a limited range of
throttle openings, and vehicles fitted
with cruise control that are often used
for long trips may develop a ‘wear spot’
at a particular load/speed position. From
a servicing point of view there is little
mileage in trying to repair the micro¬
switch types, however it is sometimes
possible to extend their life by judicious
applications of ‘contact cleaner’.
Triggering your scope to capture the
signal from the variable resistor type of
TPS ‘on screen’ long enough to critical¬
ly inspect the waveshape is quite a tick¬
lish little problem with an analog scope,
and this is where the digital storage
scope really shines.
Even so, it took me a couple of at¬
tempts to catch the trace crossing the
screen at just the right moment and
end up with the trace central in the
screen (Fig.6).
If you set the trigger point for a rising
edge on the external trigger input, and
touch the probe for the trigger input on
the battery positive terminal just before
you open the throttle with your other
hand, the sensor trace will appear fairly
centrally on the screen and you won’t
lose the first part of the rising edge. I
used a 200ms/div timebase setting and
lV/div vertical scale.
A tip: my vehicle has an electronic
voltage regulator built into the alter¬
nator, and with ‘key on engine off’, I
could just make out a high pitched
squeal emanating from the regulator
area. The TPS trace on the screen was
covered with regularly spaced AC
spikes about 50ms apart and 0.25V in
amplitude, similar to the hash you’re
hoping to see/not see, depending
whether you make your living out of
fixing motor cars. Unplugging the two-
pin plug to the regulator restored the
trace to smooth DC.
Things to look out for are ‘hash’ at the
beginning and end of the TPS trace
where the throttle sits at idle, and also at
the lower end of the rising and falling
edges of the slopes where you would
expect the throttle to spend most of its
working life.
Now that I’m looking at the printout
of Fig.6, I’ve just realised that the sen¬
sor isn’t quite set correctly! The closed
voltage should be 0.5 - 0.9V and the
fully open voltage should be 4.0 - 5.0V.
I’ll be back in a minute, after I fix it...
Back again, and it’s time for some
philosophy. I hope you are beginning
to realise the importance that the oscil¬
loscope is playing in diagnosing
customers’ complaints about their
motor cars. The digital multimeter or
‘DMM’ is a great tool and I wouldn’t
know what to do without mine, but
there are some jobs you just can’t do
without a CRO or digital storage oscil¬
loscope (DSO).
As technology brings new and ever
more complex enhancements to
everyday affordable motor cars, tech¬
nicians are being asked to lift their
capabilities higher and higher.
One approach is a list of voltages for
every pin on every ECU of every
variety of motor car, but this is likely to
produce technicians who cannot think
things through to a diagnostic con¬
clusion. I feel the only sensible solution
is to train yourself, with the aid of
equipment that helps to promote an un¬
derstanding of how things work.
In my final episode in this scope
series, we will look at some ECU out¬
put signals and how the ins and outs
interact. ❖
22
ELECTRONICS Australia, June 1995
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Moffat's
Madhouse...
by TOM MOFFAT
A little slice of heaven, in Denver
Compulsory formal qualifications or
not? That’s the big debate in the
electronics servicing industry at the mo¬
ment. In this magazine it started in the
Serviceman column (pardon me —
shouldn’t that be ‘Serviceperson’? Let’s
get our political correctness correct! Just
kidding). Anyhow the whole issue
seems to have migrated to the Forum
area (which is what Forum is for, after
all...), where the sparks have been flying
from all directions.
I particularly liked the cartoon in the
February issue showing Jim Rowe
jousting with his pen against a ‘hornet’s
nest’ full of service technicians. All of
them looked very angry, with stingers
drawn. Well, maybe I’ll join in now; I 11
go up and give that hornet’s nest a good
swift kick and then run like hell. That’s
what you call living dangerously.
There are two distinct sides to the ar¬
gument as I see it. Technicians already
within the service industry want any
newcomers to have ‘qualifications’,
before they are allowed to enter the in¬
dustry themselves. This, on the surface
of it, looks like the traditional ‘closed
shop’. On the other hand, we wouldn’t
want complete charlatans attacking
somebody’s video recorder or big ex¬
pensive TV and making a total mess of
it. Everybody out there knows this can
occur — “let’s just tweak this thing and
see what happens”.
It seems a big part of the issue would
be just what is being serviced. If a com¬
plete inexperienced dolt attacks
someone’s VCR, there’s just one victim
— the owner of the VCR — and nobody
else. But what about the same dolt
trying his hand at something like a CB
radio? “Let’s just tweak this and see
what happens”, and ‘this’ is one of
the alignment controls for the
transmitter’s linear stages. Then the
CB goes bonkers, splattering and emit¬
ting rubbish all over the band. Now
there are lots of victims — everyone
who is trying to receive on one of the
nearby channels.
ELECTRONICS Australia, June 1995
All this is leading up to my own tech¬
nical training many years ago in the
USA, and the ‘formal qualification’
resulting therefrom. The situation in
America was, and probably still is, that
anyone could fix a radio receiver or a
TV set or a stereo or anything else, with
no piece of paper required. If you
wanted to go into the servicing business,
you just hung out your shingle and went
for it. If you were a fool, you only af¬
fected the owner of the device and
nobody else. But such shoddy practices
could draw the attention of the Better
Business Bureau, and you might find
yourself out of business quick smart.
If, however, you wanted to go
into servicing two-way radios, or any¬
thing at all that could transmit a sig¬
nal, then you HAD to have a licence
issued by the Federal Communications
Commission. This meant a stint at
some kind of tech school, followed by
a horrendous examination administered
to trembling candidates in one of the
FCC’s regional offices.
I got involved in this scene while
working for the Bell Telephone Com¬
pany. I wangled my way into a job
working on microwave radio relay gear,
but since this stuff contained transmit¬
ters (of a screaming 100 milliwatts or
so), I couldn’t touch it without the
government licence. So it was off to the
American Telephone and Telegraph
Company’s technical training college in
Denver, Colorado.
The course was broken up into two
parts. ‘B1A School’ ran for five weeks
and covered fundamentals of electricity
more than electronics — volts and amps
and watts, and big batteries and gener¬
ators and current flow through wires and
all that stuff that makes a telephone ex¬
change tick over.
We were then sent back to our home
towns to let this learning sink in. Those
going on into radio were brought back
to Denver a few months later for the six-
week ‘BIB School’, where we got stuck
into electronics proper.
At the end of B1B School we were all
herded off to the Denver FCC office to
sit the exam for ‘Second Class
Radiotelephone Operator’s Permit’.
This licence would allow you to work
on microwave stuff, as well as VHF and
UHF two-way radio gear. In other
words, line-of-sight equipment only.
It was also possible, with a cer¬
tain amount of after hours self-study,
to go for the big one — the ‘First
Class Radiotelephone Operator’s
Permit’. This allowed you to work on
HF radio gear with world-wide range.
You could also be employed as Chief
Engineer in a radio or television station,
and, with a 25 word-a-minute Morse
Code endorsement, you could become a
ship’s radio officer.
Well, that sounded pretty good to me.
Even though it was the highest technical
qualification issued by the US govern¬
ment, and damn hard work, I went for
the ‘First Class Ticket’ and won. It was
well worth the trouble; I got onto the
Telephone Company’s mountain-top¬
ping microwave crew straight away, and
also landed a job as night engineer in a
radio station. A First Class ticket was re¬
quired here because the station used a
directional antenna system at night.
A lot of people groan about being
forced to get technical qualifications,
but I found the whole experience to be
jolly good fun. Each class had about 20
students, and Ma Bell had permanently
booked out the first two floors of the
nearby Olin Hotel as accommodation.
One of the big airlines had a similar ar¬
rangement for the next two floors, as
overnight accommodation for their
flight attendants. Get the picture? The
Olin Hotel was a little slice of heaven!
The fifth floor was the permanent
residence of several little old ladies,
well separated from a rather lively disco
in the basement known as ‘The Cave’.
On the Olin’s ground floor was a bar of
a more romantic nature, presided over
by a lovely black woman piano player.
So one could make contact with a likely
24
member of the opposite sex in The
Cave, and then migrate to the piano bar
if things got interesting. In the first
week I was there, this arrangement con¬
nected me with a smashing six-foot
blonde named Barbara Sims, who even¬
tually accompanied me through both the
B1A and BIB schools, as well as some
visits to Denver in between. I wonder
whatever happened to her?
One great feature of the Bell tech
school was the lab. Mornings would be
nose-down in the textbook getting the
theory, but after lunch the whole class
would move into the lab to put into
practice the things learned in the morn¬
ing. As well as the usual voltmeters and
ammeters, the lab even had things like
Lecher Lines — so you could
see the results of standing /"^
waves on a transmission line,
as well as read about them.
Practical experimentation was
encouraged in every way.
Lab activities even extended
to the Olin Hotel. On warm
evenings after class we would
head up to the roof with a case
of beer, to soak up the last
rays of the sun. Also on the
roof was this little hut from
which emitted interesting
clicks and clacks and hum¬
ming noises. We soon dis¬
covered the hut contained the
driving motors, as well as the
control circuitry, for the
hotel's one ancient elevator.
As the car would move up
and down, we observed that
many relays and solenoids
would open and close. We also
observed that you could make
the lift do your bidding if you
manually operated certain
relays with a stick. Thus, with
some carefully thought-out
relay poking, we could send
one of the little old ladies to the third
floor, instead of the ground floor she
had selected. Or one of the airline hos-
ties could be diverted to the fifth floor to
join the little old ladies. Or better still,
we could send a whole elevator-load of
hosties to the Telephone Company floor.
Mind you, these activities were only to
further our technical knowledge...
Yes, we became regular elevator ex¬
perts. There was an enormous lift in the
office building where our classroom was
located; the thing could carry the entire
class of 20 at once. We soon learned that
this lift was vulnerable too. If all 20
class members jumped up and down in
unison as the lift was coming in to land
at the ground floor, we could make it
overshoot right down to its springs at
the bottom of the shaft. When the doors
opened we would climb up to the floor
at about knee height, leaving the dis¬
abled lift for the building’s maintenance
people to investigate. They never did
work out what happened.
We all got along famously with the
Olin Hotel’s piano player, mostly be¬
cause there was a gift of flowers from
the ‘telephone boys’ every night when
she arrived for work. Little did she
know that the flowers had until recently
been resident in the grounds of the
Colorado State Capital building, which
we walked past every evening.
Speaking of the Capital, it was the
subject of yet another technical exercise
for the Bell tech school. The Capital
was built back in the gold rush days,
and the State of Colorado decided to
show how prosperous it was by cover¬
ing the building’s dome with solid gold
leaf. Gold leaf is pretty thin stuff, but it
was an enormous dome. And the view
from the guest lounge at the Olin Hotel
was dominated by that dome, only one
block away.
We would sit there, having a few
after-dinner drinkies, and somebody
would say “How are we going to get
that gold?" Just an academic exercise,
you understand, but many screwball
schemes were thought up — such as
winding coils around the dome and
melting the gold with induction heat.
A more direct approach involved
climbing up there in the dead of night
and simply ripping it off. Readers will
be comforted to know that, as of
December last year, the gold was still
intact. Anybody got any ideas?
As for the Olin Hotel, years of makin'
whoopee by the telephone guys and the
airline girls and the little old ladies seem
to have taken their toll.
Nowadays The Cave is gone, and
somebody has even filled in the swim¬
ming pool. The hotel has been taken
over by the US government’s Depart¬
ment of Housing and Urban Develop¬
ment (a bit like our Housing
Commission), and it’s now a permanent
home for disabled and unemployed
people. I do hope some of the
charm of the place is still there
for them to enjoy.
As for the Bell Telephone
technical school, I suppose it
must still exist somewhere,
because all those radio
people still gotta get their
qualifications. I just hope the
school is as good for them as it
was for me.
It’s interesting to note that
when I migrated to Australia
back in 1968, the Government
here didn’t want to know
about my First Class FCC tick¬
et. If I wanted to work as an
engineer in a radio or TV sta¬
tion, I needed a ‘Television
Operator’s Certificate of
Proficiency'.
After reading through the
syllabus, I thought I’d have a
pretty good chance of passing
- the exam, after learning such
things as new TV receiver in¬
termediate frequencies. Other¬
wise it seemed to be pretty
much the same as my FCC
ticket. But no, you couldn't
walk in and sit the exam. You
had to attend an Australian tech school
first. It had that definite ring of ‘closed
shop' about it...
If the situation comes about where
formal qualifications are needed to work
as a technician, there’s really nothing to
fear. You DO learn something — not
everything, mind you, but the theory
and practice you absorb will be of con¬
siderable value for the rest of your
working life.
But, as many people have pointed
out in the ongoing debate, none of
this schooling is really much chop
without genuine hands-on experience.
Hopefully on the COLD end of the
soldering iron! ❖
just
ELECTRONICS Australia, June 1995
25
ID® SCiEEN 3D TV
NEEDS i® GLASSES
Perth-based firm Xenotech Australia has developed a novel and patented projection 3D system
which requires no special viewing glasses or filters, and is attracting interest from around the world
because of its potential applications in ‘virtual reality’ computer displays, training simulators and ar¬
cade games. Already the company has signed a million dollar international licence agreement with
Korea’s Samsung Electronics, one of the world’s largest manufacturers of TV receivers and com¬
puter monitors.
by JIM ROWE
Although a relatively new company,
and still not very widely known other
than in Western Australia, high technol¬
ogy developer Xenotech Australia has
already attracted quite a lot of interna¬
tional interest for its innovative ‘no
glasses’ 3D projection TV system.
After testing the Xenotech system,
Korea’s electronics manufacturing giant
Samsung Electronics proclaimed it better
than anything it had previously tested,
and last October the firms signed an in¬
ternational licensing agreement whereby
Samsung is paying an initial $1 million
to fund further development, and will
pay substantial royalties when the tech¬
nology is used in its products.
The agreement with Samsung is non¬
exclusive for all territories other than
Korea, leaving Xenotech free to
negotiate further licence agreements for
other countries.
And judging from the interest attracted
by the technology, further an¬
nouncements are certainly anticipated in
the near future. All of which is quite im¬
pressive, for a company
which was only established a
little over two years ago.
So how did it all begin?
Well, the technology itself is
the brainchild of Xenotech’s
research director Angus
Richards, a young engineer
who majored in robotics im¬
aging when he graduated
from Curtin University in
1988, winning the Don
Watts Prize for his final year
project.
About four years ago, Mr
Richards became interested
in large-screen 3D displays
after inspecting a large-
screen arcade game. After
building and testing a series
of prototypes, he came up
with a system which worked well
enough to demonstrate it to investors. A
group of Perth businessmen and inves¬
tors were then sufficiently impressed to
back his research, and in early 1993
Xenotech was established.
Since then the company has expanded
its operations at Osborne Park in Perth,
and has also opened an international
head office in Calgary, Canada. Mr
Richards himself now controls Xenotech
Research, while Xenotech Australia
handles the commercialisation and
licensing of the technology, under the
control of CEO Mr John Ripp. The inter¬
national operations are known as
Xenotech Inc, with Angus Richards as
President and UK-based Mr Neil Speak-
man as Chairman.
Xenotech Inc is in fact a public com¬
pany listed on the Alberta Stock Ex¬
change, with shares held by Mr
Richards, Mr Speakman, the original
Australian investors and a major institu¬
tional investor. The two Australian firms
are its wholly owned subsidiaries.
No-glasses 3D
Xenotech’s current 3D technology is a
patented system for providing a single
viewer with a large, bright, full colour
and flicker-free television image which
is truly ‘solid’ and three dimensional —
but unlike most other systems does not
require the use of special glasses or fil¬
ters. (Although holographic 3D systems
do not require the user to wear glasses,
they provide transparent or ‘ghost-like’
images, and because of low image
brightness are generally not suitable for
use in normal ambient lighting condi¬
tions.) The Xenotech system is com¬
patible with virtually any standard TV
transmission and video recording format
(including HDTV), and is also com¬
patible with standard computer display
formats.
The combination of large image size
and high brightness level is achieved by
using a back projection system, while the
full colour and flicker-free charac¬
teristics are achieved by using two video
projectors — one to produce
the image for each of the
viewer’s eyes — rather than
the ‘L-R-L-R...’ single time
multiplexed projector used in
most previous systems. The
use of two projectors operat¬
ing continuously also avoids
the need for special glasses, as
well as increasing the average
image brightness and allowing
the system to operate in a nor¬
mally lit room.
The really novel aspect of
the Xenotech system, how¬
ever, is its use of an eye-track¬
ing system to ensure that the
viewer’s left eye always sees
the L image, and the right eye
the R image, regardless of the
exact position of the viewer’s
Xenotech 9 s Research Director Angus Richards with a
prototype of his company’s ‘no glasses’ 3D TV display
system.
26
ELECTRONICS Australia, June 1995
head and eyes. A miniature
video camera underneath the
3D display images the
viewer’s head, and sophisti¬
cated image analysis hardware
and software locates and
tracks their eyes, automat¬
ically adjusting the position¬
ing of the projected L and R
images to keep them in the
correct alignment for op¬
timum 3D viewing. As a result
the viewer’s head has the
freedom to move from side to
side or vertically, without
losing the 3D effect.
How it works
As shown in the diagrams
the Xenotech system uses a
compact folded optical sys¬
tem, in which the two video
projectors are mounted verti¬
cally behind the silvered and
highly reflective screen. The
beams from each projector
are reflected first by a pair
of 45° mirrors at the bot¬
tom of the cabinet, and then
by a partially silvered large
mirror suspended at 45° in
front of the screen —
through which the viewer also
sees the screen.
The effect of this folded optical system
is to ensure that the light from the
projectors is incident on the screen at ex¬
actly the same angles as it would be if
the projectors were positioned in front of
the screen, in the plane of the viewer’s
eyes. And as the screen is highly reflec¬
tive, the light is therefore reflected from
it at the same angles. As roughly half of
the reflected light passes through the
partially silvered 45° mirror, this light is
vered mirror (which is hinged
along its top edge) is tilted to
adjust for vertical movement.
The nett result is a bright,
clear and stable 3D image
measuring approximately 1.5m
diagonally, as seen by the
unit’s single viewer. If multiple
viewers are present in front of
the display, the current eye¬
tracking system simply ‘locks
on' to the viewer closest to the
optimum position, and
provides that viewer with the
correct 3D image.
Although the initial system is
clearly only capable of provid¬
ing this optimised 3D display
for a single viewer, it seems to
be the first really practical sys¬
tem to achieve this without re¬
quiring special glasses, etc.
And this gives it a large num¬
ber of important potential ap¬
plications, including video
arcade games, 3D computer
workstations, monitors for
remote control of industrial
equipment, simulator displays
and remote sensing. That’s
why there’s been so much in¬
terest in the technology, from
companies around the world.
However Xenotech is already working
on the development of multiple-viewer
3D display systems, using related tech¬
nology. So we can probably expect to
see further interesting developments
from this innovative Western Australian
company, before long.
Companies seeking further informa¬
tion can contact Xenotech Australia at
Suite 1,41 Walters Drive, Osborne Park
6017; phone (09) 446 3366, or fax (09)
446 3340. ❖
Mr Richards is shown here checking the operation of the
prototype 3D display, which has some of the panels
removed to reveal the works’.
therefore potentially able to reach the
viewer’s eyes at the correct angle for op¬
timum viewing.
To ensure that this occurs regardless of
the exact position of the viewer’s head
and eyes, the eye tracking system adjusts
both the position of the video projectors
and the precise tilt angle of the large par¬
tially silvered mirror. The projectors are
moved in the horizontal plane to adjust
for lateral movement of the viewer’s
head and eyes, while the partially sil-
ELECTRONICS Australia, June 1995
27
EA Reviews the new
COMPACT VI FA
SUBWOOFER KIT
If you’re in the market for a small high performance subwoofer that can handle loads of power, this
new speaker kit from Jaycar should fill the bill. Using one of Vifa’s latest 200mm bass drivers in a
compact vented enclosure, it achieves a low frequency response down to around 35Hz and boasts
an impressive power rating of 150W RMS.
by ROB EVANS
Readers with an interest in
loudspeaker construction are likely to
have noticed the name Vifa popping up
at regular intervals over the years, in
both EA and ETI speaker kit construction
articles. The respected Danish speaker
manufacturer produces a wide range of
drivers for both the home constructor
and commercial loudspeaker manufac¬
turing markets, and these have been an
ideal choice for local speaker
kits — thanks to their
availability and above all, con¬
sistent performance.
In other words, by choosing
a speaker kit designed around
Vifa components, constructors
can be confident that the
specified drivers are readily
available and the system’s final
performance will be very close
to that of the prototype.
As it happens, though, the
last Vifa based speaker system
that appeared in EA was way
back in the September 1988
issue, where we took a look at
a neat 75 litre three-way setup
based on Vifa’s P25WO
245mm bass driver.
Things had been rather quiet
on the Vifa front since that
time, until Jaycar Electronics
recently approached us with
news that their stores would
soon stock a whole new range
of Vifa systems, designed ex¬
pressly for Jaycar by South
Australian firm A ustralian
Audio Consultants.
And with its new effective
status as a loudspeaker
manufacturer, the further news
is that Jaycar is now in a posi¬
tion to directly import Vifa
drivers from Denmark, which should
help to keep the pricing of their whole
new range at an affordable and competi¬
tive level.
With the strong interest in compact
subwoofers at the moment, thanks to
the trend towards (visually) small
speaker systems and multi-channel
home theatre setups, we decided to
check out one of the smaller units in
the new Jaycar/Vifa line up: their com¬
pact 8" (200mm) subwoofer.
The JV80 subwoofer
Based around Vifa’s new M22WR-09-
06 200mm bass driver, the subwoofer
uses a conventional bass reflex (or
‘ported’) enclosure with an internal
volume of around 35 litres, which is con¬
structed from 16mm ‘MDF’ board and
has external dimensions of 600
x 270 x 300mm (H x W x D).
The enclosure panels are
finished in ‘blackwood’
veneer, and the kit is supplied
with a front panel grille
covered in plain black speaker
cloth. All in all it has a fairly
plain but functional ap¬
pearance, which is pretty much
what you need for a subwoofer
that will probably spend its
days hiding in a corner or
under a piece of furniture.
In contrast to the simple
enclosure design, the 200mm
Vifa driver used to power the
system is a rather sophisticated
device and as you would ex¬
pect, plays a major role in
determining subwoofer’s final
performance. Featuring a
braced magnesium basket as¬
sembly, very stiff paper cone
and a low damping rubber sur¬
round, the M22WR-09-06
driver has been designed for
high power applications in
bass reflex enclosures, such as
the one used here.
As part of the driver’s high
power capabilities, it also fea¬
tures a 50mm diameter long-
throw voice coil assembly and
a husky 1kg magnet assembly
28
ELECTRONICS Australia, June 1995
with a vented pole piece. And ac¬
cording to the Vifa literature, all of this
results in a nominal power rating of
150W RMS, a long term ‘music’ power
rating of 300W, and a short term pulse
power of 500W — impressive stuff from
a 200mm driver...
The Jaycar JV80 subwoofer kit sells
for an all up price of $349.45, and in¬
cludes the M22WR driver, a pre-built
enclosure and a suitably rated polyswitch
speaker protection device. The com¬
ponents are also available individually,
and are priced at $199.50 for the driver,
$139.00 for the pre-built cabinet and
$10.95 for the polyswitch. And as you
would expect from a complete kit, the
cabinet includes a grille cloth assembly,
port tube, acoustic padding and the rear
terminal plate — so that all that’s re¬
quired for the assembly stage is a
screwdriver, soldering iron and less than
an hour of free time.
Performance
The JV80 performed extremely well in
both our subjective and objective tests,
and really did demonstrate how a refined
driver such as the Vifa M22WR can
deliver the goods in a correctly tuned
enclosure. While it will certainly cost
you more than a similar unit powered by
an ‘equivalent’ low cost driver of (say)
Taiwanese origins, in the final analysis it
probably just confirms the adage of ‘you
get what you pay for’...
The listening tests- were conducted
using a couple of different subwoofer
amplifiers (one being our new 300W
unit as described in the April and May
issues), and with a variety of main or
satellite speakers. In all cases we found
the JV80 exhibited a smooth and well
extended low-end response with little
evidence of frequency doubling or
cone breakup artifacts, even at high
power levels.
This latter effect can be quite a prob¬
lem with simple bass reflex subwoofer
enclosures (as opposed to more complex
‘bandpass’ designs), since the front-
mounted speaker is coupled directly to
the surrounding air of the listening room.
This in turn means that any high order
harmonics (that is, distortion) generated
by cone flexure are quite apparent to the
ear, causing a muddy and ill defined
upper bass reproduction. Presumably, the
JV80’s impressive performance in this
regard can be attributed to the Vifa
driver’s very rigid cone assembly and
low inherent distortion.
Other than that, our listening tests also
indicated that the JV80 has a very good
transient response — as we’ve come to
expect from subwoofers based on a
driver with a relatively small cone
diameter — and it is slightly less effi¬
cient than comparable designs. This lat¬
ter point became apparent when we
compared the sound of the Vifa sub¬
woofer to a similar bass reflex unit, then
a small double-tuned bandpass design,
where the JV80 had a noticeably lower
output level in both tests.
While this effect is most likely due to
the M22WR’s fairly pedestrian efficien¬
cy figure of 88dB (at 1 W/lm), the situa¬
tion is offset to a large degree by the
driver’s very healthy power handling
capability. So in practice, you just need
to push it a little harder, to achieve the
same acoustic level...
On the objective side of testing, the
JV80 gave a good account of itself as we
expected from the initial listening
checks. As you can see from the
response plot generated by our IMP
loudspeaker testing system (Fig.l), the
frequency response is commendably flat
over the critical low-bass region between
30Hz and 200Hz. So when driven via a
suitable crossover system (a passive or
active low-pass filter) set to a typical
upper roll-off point of say 100Hz, you
could expect a smooth flat response
down to the subwoofer’s lower -3dB
point of about 32Hz.
However, we should point out that the
plot shown in Fig.l was generated in a
typical listening room with the JV80
placed about 300mm from the nearest
wall, and standing on its narrowest end
with the port opening near the floor.
ELECTRONICS Australia, June 1995
29
READER INFO NO. 8 READER INFO NO. 7
Up-to-date Information for
Design & Repair
D.A.T.A.
BOOKS & CD-ROM
□ Integrated Circuts & Semiconductors
□ Parametric Access Llbraiy on CD-ROM
■> IHS CD-ROM
IC/Discrete Parameter Database
CD-ROM contains over 1,500,000 devices and
their parameters, Australian distributors, device
pinout information and many more features.
FREE-CALL 1 800 062 299
FREE FAX 1 800 817 716
...for a FREE catalogue & price list.
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Trading as: Hinton Information Services
Locked Bag 7, Eastwood NSW 2122
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BAL SATELLITE
124 UNION ROAD, SURREY HILLS VIC 3127
TEL: (03) 888 5622
FAX: (03) 830 5846
COMPACT VIFA SUBWOOFER KIT
TIMBER: Custom wood / MDF, 16mm or more
BRACE PANEL
DIMENSIONS: External measurements assume
16mm timber
Fig.3: While Jaycar offer a pre-built
cabinet for $139, you could make
your own from these basic
enclosure plans.
While this is not necessarily the
positioning that provides the best
response curve in all cases, we found it
to be the most effective arrangement in
our situation — as we’ve found with all
subwoofers, the enclosure’s orientation
within the room has a dramatic effect on
the final frequency response.
The remaining plot shown in Fig.2 in¬
dicates the JV80’s impedance response
over a range of 10Hz to 1kHz, as
measured with our Loudspeaker Meas¬
urement System (LMS) setup. As you
can see, the curve has the characteristic
double hump shape of a bass reflex
enclosure, indicating a port tuning fre¬
quency of around 32Hz (the dip be¬
tween the humps), and shows a
minimum system impedance of about
6 Cl at low frequencies.
This impedance figure shouldn’t
present any problems, as most contem¬
porary subwoofer amps will take this
type of load in their stride.
Overall then, we were really quite im¬
pressed with our first contact with
Jaycar’s new Vifa line up, and are confi¬
dent that the other models in the range
should show a similar level of perfor¬
mance. The JV80 subwoofer will suit all
but the largest subwoofer based sound
systems, and when you consider its con¬
vincing performance, appears to repre¬
sent very good value for money.
Needless to say, you can purchase a
full kit of parts for the JV80 from
your nearest Jaycar store, or if you
have sufficient woodworking skills and
equipment, just buy the essential
components and build your own
enclosure. At Jaycar’s request, we’ve in¬
cluded a cabinet construction guide in
this article, to help those taking the latter
path — see Fig.3. ♦> •
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HEAD OFFICE/MAIL ORDERS:
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READER INFO NO. 10
DSE ‘Discovery series’ book and video:
INTRODUCTION TO
BASIC ELECTRICITY
The latest addition to the Dick Smith Electronics ‘Discovery Series’ consists of an easy to read book
and a 13-minute video, covering most aspects of electricity, energy and power. Available separately,
the book and video aim to teach the beginner about the very basics of electricity.
by GRAHAM CATTLEY
There are very few books around that
deal with the really fundamental aspects
of electronics. Most books assume some
prior knowledge of the subject, skipping
over such basic subjects as charge, ener¬
gy and power. DSE’s latest addition to
its ‘Discovery series’ does a good job in
rectifying the situation, with an introduc¬
tory video and workbook combination.
The package consists of a 37-page
workbook and a 13-minute videotape,
both of which were kindly lent to us for
review by DSE.
The large format workbook seems
quite comprehensive, containing six
chapters, which cover: The nature of
electric charge; Conductors, insulators,
electric current and voltage; Energy and
power; Voltage; and The relationship be¬
tween voltage, current and power. At the
end of each chapter are a series of
review questions — over 50 in all, al¬
though only 16 are answered in the back
of the book.
It seems though, that DSE have been a
little ambitious in trying to cover such a
large number of abstract concepts in
only 37 pages; the ampere is explained
in only two paragraphs, and the dif¬
ference between conventional current
and electron flow is covered in only
three. I believe a novice would find the
subjects hard to follow, if not confusing.
It should be stressed, however that this
is a workbook, and as such, the reader is
not expected to read the book once and
come away with a full understanding of
the subject. But while the various terms
are clearly and succinctly defined, no ex¬
amples are given for the reader to work
through in order to reinforce the con¬
cepts that they have learned.
The review questions at the end of
each chapter would have been a good
way for readers to test their under¬
standing, had answers been provided for
all of the questions. As it stands, how¬
ever, about 70% of the questions remain
unanswered, leaving the reader largely
unable to verify their interpretation of
the text.
Mind you, the author states in the
book’s introduction that the book was
written for ‘Ordinary people who have
no need or desire for an in-depth
knowledge of classical physics’. This
would seem to imply that the book is in¬
tended more to give the reader an idea of
‘what it’s all about’ than a full working
knowledge of electricity. The book fills
this role quite well. It has a nice open
layout, with good use made of boxes,
headings and pictures, and the list of
keywords at the start of each chapter
makes it easy to find information on a
particular subject.
The companion educational video is
sold separately, and gives a somewhat
‘entertaining’ introduction to the basic
principles behind electricity. It starts off
with an introduction by a man in 19th-
century costume talking about electrical
charge. It then moves on to briefly ex¬
plain the the size of atoms, the difference
between conductors and insulators, ener¬
gy, AC and DC, and the formulas for
power calculations.
It’s a shame that DSE didn’t make
more use of the possibilities available to
them through the use of a video presen¬
tation. While all the above points were
covered, the only demonstration of any
electrical effect was a charged plastic rod
attracting the comer of a piece of paper.
The use of some animation, or even a
few diagrams, would have helped mat¬
ters along no end. Instead, we get a few
incongruous shots of the Lucas Heights
nuclear reactor, and the odd still of a
lightbulb or powerline.
Again, trying to squeeze so many con¬
cepts into such a small space has not
helped. The video hops between wildly
disparate subjects with such speed that
the viewer may well be left bewildered.
With only seconds given to some sub¬
jects, there is potential for confusion.
One of the greatest problems I had in
reviewing this video was in determining
the age group of the intended audience.
From the presentation style, it would
seem to be aimed at younger viewers,
however I felt that anyone able to under¬
stand all of the points raised would be
somewhat patronised by the whole ap¬
proach. On the other hand, even if all the
subjects were not fully understood, this
video could promote an interest in an
otherwise impenetrable subject.
To sum it up, then, the book is certain¬
ly worth the $7.95 price tag, and while
the video has room for improvement, at
$14.95 it provides incentive to follow
through the book, and gives the pack¬
age more appeal, particularly to a
younger audience. ❖
32
ELECTRONICS Australia, June 1995
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rie”
When I Think Bn<k
by Neville Williams
Who can ever forget the post-war
disposals stores — like A.C.E. Radio?
A memorable aspect of the post-war era, for Australian electronics hobbyists, was the appearance
of military surplus disposal stores offering an intriguing range of bits-and-pieces, and redundant
built-up units at prices which were often a fraction of what they might otherwise have been. Useful
at the time, many of those same bits have since become interesting ‘collectables’ for public and
private museums. Pardon me if I ramble a bit, but it’s that kind of a subject!
First a personal observation: At one
stage in the 1960s, at the height of the
disposals era, I had seemingly acquired
enough bits and pieces from disposals
stores and elsewhere to start a modest
museum of my own — posing a threat to
our domestic living environment and the
space available for the family car!
I recall that one stout, bulky car¬
ton contained an Australian made
4 LW’ (light-weight) radar
transmitter, complete with mag¬
netron but utterly useless for
anything other than its original
purpose. A few years earlier, its
very existance had been a
closely guarded secret, but I
had later staggered away with
one for virtually nothing —
brand spanking new, by cour¬
tesy of Jack Lewis of the Clas¬
sic Radio group.
At the other extreme, in terms
of utility, I picked up a Faton
SG-1 signal generator from
A.C.E. Radio — again cheaply,
because it wasn’t working. But,
given a few evenings of TLC
(tender loving care), it came
good and has worked ever since
on my bench — valves and
electrolytic capacitors not¬
withstanding!
An in-between acquisition
was an American made field
multimeter, in a steel case,
using a large 50uA movement
— this was before the era of
protection circuitry. 1 hesitated
to use it for everyday bench
work, because of its bulk and vul¬
nerability to inadvertent measurement
overload, and my faithful old Calstan
1000 ohms/volt meter still copped most
of the work.
For the rest, most of my petty cash
went on valves — dozens of them —
from EF50 and 6AC7 RF pentodes to
807 beam tubes, 866 rectifiers, and im¬
posing transmitter ‘bottles’ like the 803.
On the job — a smiling Joe Ellison , posed against an
assortment of valves in one of the tidier corners of
the A.C.E. Radio display.
These, and useful little two-inch square
meters, which turned up regularly on
the bargain counter at Prices Radio in
prestige brands like Ferranti, Weston
and Jewell.
Drawing on my boxes of ‘goodies’, I
built up a multi-band VHF transmitter
using ‘disposals’ crystals re-ground by
R&H 's then Editor, John Moyle. A few
months later, I came across an ex-dis¬
posals calibrated, tuneable
aircraft transmitter which proved
very successful as an add-on
VFO. Was it from Walthan Trad¬
ing, Metropolitan Radio, Paragon
Radio, Deitch Bros, Lance Chap¬
man, Mike Sheridan or someone
else? I can’t remember...
Another British aircraft trans¬
mitter, ratchet tuneable across the
UHF band, set me up on the
144MHz amateur band —
provided I didn’t attempt to
change the preset frequency too
often. Operating within the noise
field of a Rolls-Royce Merlin en¬
gine, one mightn’t have noticed;
but in the comparative quiet of a
suburban backyard ham shack,
the ratchet preset tuning system
generated a passable noise
simulation of a machine gun —
all by itself!
Both transmitters, along with a
five-metre job from mainly dis¬
posals bits, have long since been
pensioned off and there is once
again room to move in the
house 1 . Such, for me, was the lure
of disposals equipment.
34
ELECTRONICS Australia, June 1995
Home-ground crystals
Former Editor John Moyle’s pride and
joy was a heterodyne type frequency
meter which, as I remember, he picked
up from a Melbourne disposals dealer.
Using type 30 battery triodes and de¬
pendent on its individually calibrated
handbook, it was a tedious instrument by
modem standards; but he used it to re-
grind numerous crystals for his own
transmitters, while also helping out other
members of the magazine staff.
Not surprisingly, some of John’s own
petty cash went on stray crystals which,
in those days, were mostly mounted in
hand-assembled plug-in holders — some
from overseas, others from AWA and
Melbourne’s Max Bowden.
Similarly for other members of the
R&H staff, with the further observation:
every one seemed to have hoarded hanks
of assorted coaxial cable bearing obscure
type numbers, for possible use with
ham rigs or TV sets. All too often the
hanks proved to be of inadequate length,
unsuitable impedance or too ‘lossy’.
Any number of other old timers, I
guess, will recall having invested in ex¬
disposals parts with the best of inten¬
tions, often to realise that, months later,
many of the bits were still sitting in their
original packing, untouched. Like me,
they were on their way to having their
own mini-disposals store on site!
One could doubtless ramble on in
this fashion, but I will simply add an
observation by Selwyn Sayers, EA's
long serving Advertising Manager.
Having joined the staff around 1960, at
the height of the disposals boom, he
branded this present article as “timely
because, in advertising terms, it marks
the end of that whole era’’.
In point of fact, the notion of covering
wartime electronic ‘disposals’ stores in
these columns arose in part from a letter
mentioned in the March issue, from
Terry Parritt of Upper Hutt, NZ. Terry
said he had picked up a basic familiarity
with radio in the 1930s from discarded
20’s-style radio sets and government
surplus bits, plentiful in second-hand
stores in the UK at the time. He
wondered whether we’d had similar
stores in Australia.
About the same time, Editor Jim
Rowe mentioned in conversation an
ex-patriot English radio engineer who
had inquired whether we planned to
cover Australian surplus stores like
A.C.E. Radio, which he used to visit
regularly in the old days. If we were
interested, he had taken a number of
colour slides at the time, which would
be available for publication.
Whenfnrm'Jfri'in vSSf 8 ^ Marrickville ’ J ust More the building was sold.
19 J 4, l he com P an y was registered as Excelair Radio and
supplied built-up radio chassies.
When I finally got to talk to the
aforesaid radio engineer, John Rich, he
proved be a much younger man than
Terry Parritt — bom in 1940. But he
was nevertheless able to confirm that
well stocked second-hand (‘junk’)
radio shops had indeed been plentiful
in the UK in the 1930s. Such had not
been the case in Australia until after
WW2 — an era, as I said, that is now
passing into history.
Australian stores
It gave me cause to recall the early
1930s when, as an impecunious wirer, I
used to haunt the wireless shops in the
Sydney CBD during my lunch hour —
partly to fill in time and partly in the
hope of spotting an affordable bargain.
There were three or four shops in the
Royal Arcade which, very occasional¬
ly, offered a tempting addition to their
standard display. Near the George
Street end was the store which
originally belonged to Mrs F.V. Wal¬
lace. Further down was Joe Keeps’
shop, carrying telephone oddments
from the PMG Dept.
Across the road, in nearby Pitt Street,
was (Joe) Levenson’s Radio, noted more
for buzzers, Morse keys, mini-telescopes
and other such technical toys than for
radio parts.
Further up Pitt Street was Radio
House, with an excellent display of radio
and electrical parts, keenly priced but
with few clearance bargains. And then
there was Murdochs, a men’s emporium
diagonally across from the Town Hall,
with a handyman section stocked with
tools and radio oddments but, again, few
clearance bargains.
If Australian hobbyists were to collect
unwanted surplus wireless components
in those days, they had to obtain them
privately rather than over the counter.
At the end of WW2, however,
Australia was suddenly awash with
surplus military equipment. It was then
that entrepreneurs with some knowledge
of electronics and capital to spare
realised that there was money to be
made, by buying surplus electronic
whatnots in bulk from government stores
and marketing them to enthusiasts direct¬
ly and/or by mail order through technical
publications like Radio & Hobbies. No
less to the point, apart from long term
enthusiasts, there was a whole new
generation of potential hobbyists who
had been introduced to electronics
during recent military service.
Their would-be suppliers ranged from
novice investors to executives of estab¬
lished electronic firms who saw the
chance to grab a share of the action.
Harry Carter of A.C.E. Radio, specifical¬
ly mentioned by John Rich was one of
the latter.
We are indebted to the late Allan Fai¬
son for an account of how the system ul¬
timately worked out in practice (EA,
Dec.’92).
Getting their bargains
Government Stores would publish
details of what was to be auctioned, at
certain times and places. Professional
dealers would confer beforehand and
decide on the likely demand for the
ELECTRONICS Australia, June 1995 35
that he had endured more then his share
of overcast, biting winds, sleet and cold.
He had accordingly headed for Australia,
where he found that he could pursue his
interests and career in a warm environ¬
ment, under sunny skies and ‘be paid
money to do so’!
In fact, he has done just that for the
past 25 years, tending to specialise in
digital control of industrial processes
‘from blast furnaces to icecream
factories’ — much of the work being at
the ‘cutting edge’ of design. He worked
with Philips in the early 1970s, during
the development of their microprocessor
controlled traffic signals — a world first.
dirty, to reclaim and maintain historic
boats/ships for the Sydney Maritime
Museum; and why he is also on the
lookout for the bits and pieces to recreate
historic wireless rooms on such ships.
Again, when the subject turned to the
‘Sixty Milers’ that once hauled coal
from Newcastle to Sydney for the coal-
gas suppliers, before the days of
natural gas, he told me of the North
Sydney terminal that he had visited; of
the wheelbarrows and shovels that
were still right where the workmen had
left them; and, as it were, the ghostly
presence of the men themselves!
As for voices, he is also active in oral
history and is well acquainted
with the efforts of the ABC’s
Stephen Pratley, producer of the
historic wireless history tapes
‘Bright Sparks’.
But, jumping several decades,
he is also on the committee of
the Computer Museum Society,
and grateful that examples of the
‘world first’ Australian Philips
digital traffic controller, which
are just being decommissioned,
may be offered by the RTA
(Road Traffic Authority) to
museums, thus preserving them
for posterity.
Surprise! Surprise!
Getting back to A.C.E. Radio,
he said that one of his most in¬
triguing discoveries among the
‘junk’ was a couple of very
light weight 19-inch equipment
racks. He was told that they
once held communications
equipment carried on sleds and
used by an Australian expedi¬
tion to the Antarctic. Only the
racks remained...
In conversation, I mentioned
finding a particularly hand¬
some transmitting valve that
had probably belonged once
to the Royal Navy. The
glasswork was flawless and un¬
clouded, the nickel electrodes as
shiny as the day they were
mounted and the nickel base similarly
unmarked. It had adorned our mantel
shelf at home with all the aplomb of a
Venetian ornament, until it was crowded
out by family photos.
Said John Rich: “There were boxes of
magnificent old valves like that at A.C.E.
Radio. I tried to talk Joe Ellison into sup¬
plying polished wood stands, which
could be drilled to accept the base pins,
but he wasn’t interested. They would
have made magnificent ‘conversation
pieces’ on an executive table...”
various items on offer, an end price that
would appeal to the public and how
many units each dealer would be
prepared to buy.
At the auction, bids were convention¬
ally invited first for one-off items so that
private buyers could be accommodated.
Bids were then called for specified lots,
and only one prearranged dealer would
appear to be interested, with no more
than purely token competition. A bid
having been accepted, orders would be
placed to cover the total needs of the
group. Similarly for other items, with
different dealers leading the bid¬
ding on each occasion.
At the end of the day, there
would be a grand settlement
with members of the group
covering their respective cash
committments and arranging to
pick up their share of the pur¬
chases. Chatting with Lance
Chapman during the preparation
of this article, I mentioned what
Allan Faison had told me. Said
Lance: “The ‘cartel’ approach
was the only effective way for
us to buy!”
Collusion it undoubtedly was,
but it was probably reflected in
a more attractive price to the ul¬
timate purchasers. One also has
to take into account that a sig¬
nificant quantity of war surplus
and lend-lease equipment never
went under the hammer at all —
being written off, dumped at sea
or buried as landfill in disused
brick pits. Anything to get rid of
the stuff!
(I mentioned this to Geoff
Wood, a former advertiser in
this magazine, who told me
how, as a member of the RAAF
maintenance staff and under or¬
ders, he had personally super¬
vised the postwar dumping of
surplus aircraft engines and
machine tools into the depths of
Darwin Harbour...)
In conversation, John Rich said that
his own interest in disposals stores —
A.C.E. Radio in particular — was not
primarily as a source of components for
personal use, but rather because such
stores were a repository for apparatus
and components that belonged to
electronics history.
Paid to enjoy himself!
Bom in the South of England, he had
trained and worked in the UK as an in¬
dustrial electronics engineer until he felt
Once the kitchen sink, by the time this picture was
taken there was barely enough room remaining to
make a cup of tea.
Chatting informally about such mat¬
ters, as a couple of C-60 tapes slid un¬
obtrusively through my cassette
recorder, I sensed a man who combined
a practical respect for modern
microtechnology with a genuine affec¬
tion for the patient and ingenious
methodology of other days.
That is why his mind returns easily to
the historic RAF (Royal Air Force) and
RN (Royal Navy) installations which
still dot Britain; why he now spends
much of his spare time getting his hands
WHEN I THINK BACK
36
ELECTRONICS Australia, June 1995
Joe would have been happier if
they’d been like the stacks of high fre¬
quency power transformers he collected,
unusable on 50Hz mains. He could have
piled them in a heap and flogged them
off to a scrap metal dealer.”
There were also lots of cathode ray
tubes, as I recall, some still in their
original cartons, others piled bare into
boxes as exposed and vulnerable as eggs
in a paper bag. The most useful ones
were American 5-inch diameter 5BPl’s
and British 6-inch VCR97’s. I tried them
both in a home made bench
oscilloscope and a junk-
based TV receiver, producing
a green picture the size of a
visiting card.
Quite a few readers fol¬
lowed suit (j Editors Note: In¬
cluding me!), and found as I
did that one would logically
buy two or three extra tubes
for future use — in case the
originals became gassy. The
spares weren’t heavy, but
they did add significantly to
the stuff piled up in the
home!
In fact, I also took home
couple of 10-inch diameter
tubes in the forlorn hope that
they would provide a larger
TV picture. Most of them,
unfortunately produced a
blue, long persistance image
which was hardly ap¬
propriate for the action on a
TV screen. Worse still, they
tended to build up a static
charge on the screen which
smeared the image randomly,
like an oil slick on a wet
road!
Short on facts
So much for what I warned
at the outset might be a ram¬
bling treatment of the sub¬
ject. When it comes to the
actual history of A.C.E.
Radio, 1 find myself lamen¬
tably short of facts. Maybe
just maybe — there is someone out
there who can help fill the gaps.
According to John Rich, Harry Carter
set up a business at the Victoria Road,
Marrickville address in 1934 — about
the same time that I left High School and
started work as a wirer at Reliance
Radio. Joe Ellison had told him that
Harry had claimed advertising support of
Radio & Hobbies in just about every
issue since Vol.l, No.l.
A check through as many issues as I
had access to suggested that the one ad¬
vertiser who can justly claim ‘never
missed an issue’ would be RCS Radio.
John also alerted me to the fact that
Harry’s company had been registered
under the name ‘Excelair Radio’, which
I remembered vaguely but could not find
in my 1939 copy of Mingay’s Radio
Trade Annual. Nor was there any men¬
tion of Harry Carter himself.
However, thumbing through my time¬
worn bound volume 13 of this magazine
from April 1951 — 1 came across
regular full page advertisements for Ex¬
celair Radio, offering kits for radio
homebuilders and/or a range of complete
chasses, built up and tested. Harry Carter
had set up the Marrickville cottage as a
small radio factory, possibly supple¬
mented by enthusiasts working on a cot¬
tage industry basis. Either way, he was
obviously doing well enough to pay for
full-page advertisements.
Some issues contained a second Ex¬
celair page offering war surplus
clearance items, as also were Prices
Radio, Metropolitan Radio Supplies,
Deitch Bros, Motor Spares Ltd,
Electronic Equipment Co, Surplus
Stores, Waltham Trading, Goodman_
an incomplete list, in the order I came
upon them. Looking at the contents, it is
evident that, having established their
credibility with war surplus trading,
some of them had also tapped into left¬
over stocks held by local manufac¬
turers/distributors.
All in the family
At about this same time (1952) Harry
Carter was joined by Joe El¬
lison, who sealed the arrange¬
ment by marrying one of
Harry Carter’s daughters,
thereby becoming a son-in-
law.
Curiously, Harry gained
another son-in-law in the per¬
son of Jack Lewis, the owner
and manager of Classic
Radio, operating from
premises in Parramatta Rd,
Ashfield — obliquely across
the way from the old AWA
factory. Jack also supplied
built-up equipment, but had
separate outlets to handle dis¬
posals trading.
Returning to Harry Carter, it
is evident from the advertise¬
ments that disposals activities
gradually swamped Excelair
Radio. Room after room in the
Victoria Road building — an
ordinary brick cottage — was
filled with disposals equip¬
ment, as was the original front
verandah and patio space at
the rear. After that the pur¬
chases were stacked in the
backyard, with or without
protective tarpaulins.
I well remember, as do
others, the dismay at seeing
equipment in crates or
cardboard cartons, dripping
wet in the rain — equipment
for which we might otherwise
have found a nice, dry spot on
our own workbench!
Inside the cottage, out of the rain, the
‘office’ had shrunk to a mere break in the
endless procession of boxes and bits,
with just enough space to accommodate
a chair and kitchen sink, telephone,
paperwork and a few relevant
magazines. Nearby was the wherewithal
to make a cup of tea. Elsewhere, accord¬
ing to John Rich, all evidence of a one¬
time radio workshop had been buried
under boxes and bits.
In 1950, the name of the company had
been changed to ‘A.C.E. ’ which signified
ELECTRONICS Australia, June 1995
£ +***+★★★★ PHONE
LA3845
136 VICTORIA RD. MARRICKVILLE,SYDNEY NS-W
iVENINGS and WEEKENDS- - 1 ^ 15 “^ ~ ^7008
--g™SL2!!“-
AMERICAN WALKY genemotor for
TALKY PORTABLE TV
New Smirk Aircraft
CLOCKS
£34/17/6
New Trommirter Valves
JglWZL. £2*. JV jjw’rTron.formm
' H r **•* 5K11 i '! !
£36
NEW VALVES
• • •*’
NEW 24V MOTORS «”•’
^ RELAYS
£!/!• * JJJJ JJJJj L
*' !• »!*•• • *** irot ** 1 ‘ jjjl
MINIATURE
HI-POWER MOTORS
|f> ^ f CrwM.. B
,a, ‘' fT/nTT ""_
TELEPHONES
Sunward PJH.C. l»r>.
**£%!■ -
£6/IOA
NEW RT.^ METERS
To/6**
£32/10 /
NEW 240V a.C.
^°3° R s
£2/17 /6
DON 8 TELEPHONE -
*7r*w. new vacuumj*umps
£2/7/6
£1/7/6
WIRE
"H/T
NEW 2V Vibrotor Power Supplies
*S£ u «!l u i*I2!? I ' ri/’n/d"“
Hard MW Can.
15/-
' TYPE f. TELEPHONES
>»< tirlrn Ordn
£5/15/ -
NEW SPOTLIGHT
GLOBES
NEW RESISTORS
B/6 rrn.J : .
NEW CONDENSERS
** iT/V"'
_ r»M. i >
VALVE Cr CIRCUIT
TESTERS
7/6
Although somewhat reduced in size, this reproduction of a
page from an A.C.E advert in May 1959, gives a good idea
of the range of disposals items on offer.
37
READER INFO NO. 12
WHEN I THINK BACK
The UV People |
ETCH TANKS
• Bubble Etch • Circulating
LIQHT BOXES
• Portuvee 4 • Portuvee 6
• Dual Level
TRIMMER
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PCB DRILL
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MATERIALS
• PC Board: Riston, Dynachem
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• Dynamark: Metal, Plastic
• AUSTRALIA’S N0.1 STOCKIST *
40 Wallis Ave, East Ivanhoe 3079.
Phone (03) 497 3422, Fax (03) 499 2381
Amplification, Communications and
Electronics. Hence the full points after
each letter in the registered logo.
When 1 compared notes with Selwyn
Sayers, EA’s Advertising Manager, he
recalled some of the agonies of the
company’s advertisements, of which I
was also a witness from the editorial
chair. In the ‘old days’, when Excelair
was seeking to promote new radio chas-
sies, the advertisements were well
planned and attractive — probably the
work of a professional advertising agent.
Difficult adverts
When the emphasis turned to non¬
descript disposals oddments, the
presentation changed from commercial
art into an urge to cram in as many
items as possible. Compositors were
presented with tiny illustrations and
descriptive paragraphs to be set in the
smallest practical typeface.
For the following month they would
be likely to receive a copy of the pre¬
vious advertisement, with hand-written
instructions to ‘change this’, delete
that’, or ‘insert this instead of’. As the
months rolled by, the instructions be¬
came more involved, requiring more fre¬
quent reference to past issues.
These days, with computerised setting,
they wouldn’t have posed such a prob¬
lem, but 20 years ago illustrations in¬
volved zinc ‘blocks’ attached to
rectangles of type metal. Text comprised
individual lines of type metal, set and
cast by linotype machines. To make up a
page involved stacking and packing the
lines and blocks into a page sized metal
tray, to satisfy the layout instructions.
As if that wasn’t problem enough, the
contents of the tray rested face up on the
compositor’s bench so that he had to
manipulate in metal a mirror image of
the layout instructions to produce a
finished page that was the right way
round. Needless to say, setting up an
A.C.E. advertisement was not the most
sought after assignment among the Fair¬
fax ‘comps’!
One other story related by Selwyn
Sayers is worth re-telling.
Completely hemmed in by disposals
whatnots, Harry Carter found it difficult
to keep up with his mail, with the result
that Selwyn Sayers received more than
his share of complaints about A.C.E.’s
slow response to orders. He, in turn used
to ring Harry to warn him that he’d have
to adopt a better system — or risk
having his advertisements refused.
A different level
Harry was reputed to be affable and
honest, even if a ‘rough diamond’, but
he seemed not to comprehend why a
bloke ‘in the sticks’ would need to
write to the magazine, just because
A.C.E. took a few extra days to fill his
order! Did they think he, Harry, was
some kind of a shyster?
When Sel finally threatened to ‘pull
the plug’ on A.C.E. for the next issue,
Harry felt sure that the publishers had
a hidden agenda — their real concern
38
ELECTRONICS Australia, June 1995
tou 9 h ’ but J here Just wasn’t room inside for this lot. Visitors to A C E
Radio were often dismayed to see surplus gear standing outside in the rain.
was probably his ability to pay the bill.
His response to Sel: “I want to talk to
your boss”!
At the time, that translated into Angus
H. McLachlan, the urbane General
Manager of John Fairfax Ltd and a direc¬
tor of Associated Newspapers Ltd, then
publishers of this magazine. Arrange¬
ments were duly made for Harry Carter
to meet Selwyn Sayers outside the
Broadway building at a certain time, and
be conducted to the management offices
on the top (14th) floor. This floor was
referred to sometimes as ‘Heaven’; at
others as The Mausoleum’, prompted
by its demurely panelled wooden walls,
acres of carpet and pervading silence.
Ordinary mortals entered only when
bidden, with bated breath and respectful
countenance.
When Harry arrived at the front
entrance of the building, he’d come
direct from his shop in his work clothes:
non-descript trousers, odd shirt and
socks, old style tennis shoes, and carry¬
ing a time worn Globite case. Thus clad,
he was ushered into the Management lift
to the 14th floor and thence into the
GM’s sanctuary.
The reason for the visit was duly ex¬
plained, but Harry seemed determined to
make one particular point. Picking up the
Globite case, he unclipped the lid and
emptied the contents all over
McLachlan’s desk — a great untidy pile
of banknotes! This with an insistence
that I ve got the money. I can pay my
bills, better than you all seem to think!”.
Who said what next is not part of the
story. All I can say is that Harry Carter’s
adverts continued to appear, and readers
complaints about poor service seemed
to diminish. Mission accomplished!
In 1970, Joe Ellison became the owner
of A.C.E. radio and it was from him in
the 1970s that John Rich picked up most
of the information and his impressions
relating to the disposals era in Australia.
What became of A.C.E.?
So what happened to A.C.E. Radio?
John says that Joe Ellison decided ul¬
timately to sell the business and move
out of Sydney. Seeking further infor¬
mation, I asked repeatedly where Joe
went and where he is now, but no one
appeared to have the answer. I simply
don’t know.
Both John Rich and Selwyn Sayers
said that the business had been brought
by a Paul Fullagar, who moved it ‘lock,
stock and barrel out Manly way’. In so
doing, he forfeited the customers who
had habitually dropped into the Marrick-
ville premises ‘to have a sticky’ — but
he didn’t attract an equivalent number
from his new locale. As such, the venture
was a failure.
Paul Fullagar, I was told, donated the
best of the antique equipment to local
schools, etc., and consigned the ap¬
parently unsaleable residue to the tip.
John Rich tells me that the A.C.E. cot¬
tage has been replaced by a modern
building. But maybe, just maybe, some
young secretary on the site may one day
glimpse a shadowy figure in workclothes
and tennis shoes, soldering iron in hand,
bending over a radio chassis... ❖
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READER INFO NO. 13
ELECTRONICS Australia, June 1995
39
FORUM
Conducted by Jim Rowe
The fury of some radio amateurs ,
when their wallets are threatened ...
„„ o .wiHoHK/ ‘hpated’ resDonse to my editorial in the March issue commenting on the
ifejrssSSSsSSSS^SSSS
attitudes of at least some members of the amateur radio fraternity.
As I mentioned in the March editorial
itself, I expected to be a bit unpopular
with at least some amateurs when it was
published. That’s because I’ve learned
from past experience that in this kind of
situation, quite a few hams will regard
you as ‘the enemy’ unless you take a to¬
tally one eyed, pro-ham position. And
there are times when it simply isn’t easy
to be this narrow and partisan in outlook...
Still, I must confess that in this case I
was somewhat taken aback by the level
of personal abuse in some of the mis¬
sives. Clearly the people concerned were
very upset, and anger overcame what¬
ever good manners and objectivity they
might normally have displayed.
As you’ll see from some of the letters
I’m reproducing, some people didn’t
hesitate to accuse me of bribery and cor¬
ruption. One accused me of single-hand¬
edly engineering the near destruction of
amateur radio; others have demanded my
resignation, while yet another sought to
get me fired. To paraphrase an old saying,
it seems that Hell hath no fury like some
amateurs, when their wallet is threatened!
It’s interesting that the main thing
most critics siezed upon was my small
error regarding the lack of rises in ama¬
teur licence fees over the last 10 years.
As they all rushed to point out, I was
certainly wrong here — the fees have
risen in that period from $23pa to $37pa,
as I noted last month.
It was clearly an error, although as
various people have commented, not re¬
ally a major one. But from the huge
amount of heat generated, it’s clear that
the error was important not so much in
its own right, but for the opportunity it
gave the critics to ‘have a go’ at me...
By the way, I gather that as well as
becoming the target for quite a stream of
this direct ‘hate mail’, I was also the sub-
40 ELECTRONICS Australia, June 1995
ject of numerous ‘flaming’ messages on
the amateur packet radio network. I m
told that some of these messages were
fairly nasty, too — even for the packet
radio network, which has some notoriety
in this regard.
Mind you, I’ve been told that some of
the packet radio messages which circu¬
lated about senior staff members in the
Spectrum Management Authority were
particularly nasty — so compared with
them, I probably escaped quite lightly. It
looks as if some people lose all sense of
propriety and good manners, when they
believe they can ‘hide’ behind a com¬
puter keyboard rather than confront peo¬
ple directly...
I’m sure that most people in amateur
radio wouldn’t dream of descending into
this type of behaviour, and that those who
do make up a tiny ‘ratbag minority’. This
makes it all the more unfortunate that
these people are much more visible than
the well-behaved majority, and lower the
image of amateur radio in a manner quite
out of proportion to their numbers.
For example I believe that some of the
nastier packet radio messages about
SMA staff have been shown to both the
Minister for Communications and his
colleagues in Cabinet — which would
almost certainly have done much more
to tarnish the image of amateur radio in
their eyes, than any small error in my
own editorial.
The critics speak
But let’s begin. Probably the first criti¬
cal letter to arrive, following the publica¬
tion of my March editorial, was this one
from Mr Will McGhie VK6UU, of Les-
murdie in Western Australia:
Being a long time consumer of Elec¬
tronics Australia since 1966 and a radio
amateur, I was disappointed in your edi¬
torial on the large increase to amateur
licence fees.
There has been considerable amounts
of misinformation and you have suc¬
ceeded in spreading it even further. To
quote from your editorial, ‘Amateur li¬
cence fees haven’t risen for about 10
years’. Wrong...!!!
It even surprised me, when I went
back over my past licence fee costs:
1995 $37 1987 $26
1994 $36 1986 $23
1993 $35 1985 $21
1992 $35 1984 $19
1991 $35 1983 $19
1990 $34 1982 $15
1989 $32 1981 $14
1988 $28 1980 $10
Even though the print was a little hard
to read on some of them and may not be
spot on, 1 hope you get the message. You
are wrong. In fact I would have at a
guess that amateur licence fees have in¬
creased faster than the CPI...!
Other aspects of your editorial are
also incorrect, such as ‘Prolonged nego¬
tiations between the WIA and the SMA
that the new fee structure has been whit¬
tled back’. Wrong...! Go and ask the
WIA if they had prolonged negotiations
with the SMA over the new fee structure.
And also your comments on the
amount of spectrum space amateurs
have access to is misleading. Most of it
is on a secondary basis, and is only ours
until someone else wants it.
By my calculations only 20.47% of
frequencies allocated to amateurs are on
a primary basis. In the region from
1.8MHz to 148MHz only 6.1 % is pri¬
mary amateur. And this figure is dis¬
torted high due to the unwanted 1 . 7MHz
at 28 to 29.7MHz-
And your comment on what is happen¬
ing in other countries may be true about
commercial users paying more equally for
what they use, but it is not true for Ama¬
teurs in most if not all other countries. I
gather you have not seen the comparisons
done with other countries. Packet radio
has been full of this information.
All in all Jim, very poor journalism.
Swallow hard, check your facts and then
write a retraction.
As you can see, Mr McGhie was clearly
unhappy, but was at least fairly civil. It
became clear later, however, that he had
put a copy of his letter on the packet radio
network - and it was perhaps not coinci¬
dental that many of the letters and fax
messages from other critics turned out to
have very similar passages.
You 11 notice that Mr McGhie shows
us what has happened to licence fees
oyer the last 15 years, just to emphasise
his point.
As I mentioned in last month’s edito¬
rial, I believe it’s not in the best interests
of amateur radio to expand on the rea¬
sons for the negotiations between the
SMA and WIA having been delayed; in
describing them as ‘prolonged’ I was
wrong, but this was basically because I
was trying to be charitable to the WIA.
One further point, before we go on.
Despite what Mr McGhie and many of
his fellow critics seem to think, my ref¬
erence to the amount of spectrum ‘real
estate’ allocated to amateurs was based
only on their primary usage rights. I was
not counting the bands where amateurs
have only secondary rights.
The fact is that below 30MHz, in the HF
bands, amateurs have primary rights to
3.025MHz of spectrum; below 150MHz,
the figure grows by another 6.0MHz, to a
total of 9.025MHz. And this is in absolute
terms far more than just about all other
users, apart from the military.
Many of my critics have tried to mini¬
mise this, by talking about percentages
and whatever; but the fact remains that
amateurs DO have access to a sizeable
amount of space, in a spectrum that’s
coming under more and more pressure...
Moving on, here’s another example of
the faxes from critics who were quick to
sieze upon my error regarding the li¬
cence fee rises. It came from David
Horsfall VK2KFU/VK2ZTB, of Wa-
hroonga in NSW:
I refer to your editorial on page 5 of
the March issue of EA. Whilst you are
certainly entitled to your opinion, no
matter how unpopular it may appear to
make you, you could at least get some
basic facts straight.
1 quote: Amateur licence fees haven't
risen for about 10 years... ' I don f t know
who's been paying your fees for you, but
mine have risen by about $1 per year in
the twelve years that I have been li¬
censed. Is this some new meaning of the
phrase ‘haven't risen' with which I was
hitherto unfamiliar?
As you can see, Mr Horsfall was brief
and to the point, although he couldn’t
resist that little touch of sarcasm.
More constructive
Rather longer, and somewhat more
constructive, was this fax from Dr Mur¬
ray Kelly VK4AOK, from Graceville in
Queensland:
/ suspect your editorial in the March
1995 issue which was in favour of in¬
creasing Amateur licence fees was writ¬
ten to stir the possum. After all, the last
good response and ensuing bun fight in
Forum was from the Amateurs too. Here
is my $.02 worth.
The primary space in the spectrum be¬
tween DC and 24GHz occupied by the
Amateur Service totals 9.05MHz or
.038%. Allocations that are secondary
are worth diddly-squat commercially
and any amateurs working at 24Gigs
and above deserve a medal, not a fee
ELECTRONICS Australia, June 1995
41
FORUM
rise. Secondary allocations are usually
shared with the military on a ‘good
neighbour’ basis and if the military cant
accommodate that, then God help us if
they ever meet a determined enemy.
Assuming the Spectrum Management
Authority (SMA) collect about $35 from
each Amateur station, and there are about
18,000 of them, they raise $600,000 for
those 9.05MHz or 6.6 cents/Hz. If they
were to raise 6.6 cents/Hz over the whole
24GHz, they would be collecting $1.6 bil¬
lion dollars for the Australian taxpayer. I
doubt they are.
The SMA questions that the Amateur
Service should have ‘so much’spectrum,
as if the Amateur bands were some sort
of wastelands. The question that is never
raised is, ‘what do they use the spectrum
FOR?’ That would provoke an answer
too embarrassing by far. Amateurs are
raising Australia’s electronics awareness
and education, generally, and at zero
cost to Canberra. The Government is do¬
ing nothing to help despite the rhetoric
of 'The Clever Country’.
I suggest a more realistic view would
be that the Amateur bands are the Na¬
tional Parks Reserves of the radio spec¬
trum. Like the land itself, the
Government doesn’t actually own the
stuff but is the people’s management
body for that resource.
It has been said that National Parks
should be set at 10% of the land area.
Australia is ‘way behind' other nations
here but the primary spectrum allocated
to Amateurs is even worse at .038% of
24GHz. The Amateur has paid his entry
fee to this park by studying in his own
time and at his own expense (the exams
don't come cheaply any more) and sup¬
plying his own equipment. There is a
good case there for following the US
lead and dropping fees altogether. It
would make more sense to stop wasting
money collecting the $600,000 and
down-size the staff of the SMA.
/ disagree with your comment that the
typical Amateur uses transceivers etc.
costing over $2000. Most of my acquain¬
tances use second-hand gear, which often
sport those FETs with pilot lights. In any
case, would you condemn us to using the
equivalent of a pencil and paper in this
age of $2000+ PC word-processors? Not
every home has a PC yet, but that day
approaches us quickly. Why shouldn't we
Amateurs have nice things, too?
For some reason it is commonly as¬
sumed that all amateurs are inventors
and if they are not coming up with new
ELECTRONICS Australia, June 1995
and bright ideas all the time, there must
be something wrong. On the other hand
it is never expected that professional en¬
gineers should all be inventing madly
nor indeed journalists should write liter¬
ary masterpieces every week (when did
you write your last prize novel?). The
Amateur environment serves other pur¬
poses. The inventive are given a milieu
to try their ideas with like minded peo¬
ple, something that would be difficult in
any industrial workplace unless that
person was involved in the R&D Depart¬
ment. Even I have a patent allocation for
an RF device even though it is miles out
of my work field. Have you?
It surely must be significant that Japan
has a ratio of 20:1 with Australia with
regard to Amateurs per head of popula¬
tion. In Japan there is nearly one Ama¬
teur for every 50 people. Here, it is one
in a thousand. It would be hard to deny
that this just might have something to do
with that country's world pre-eminence
in the electronics field. The youth are
encouraged into radio, not discouraged
by high licence fees. Amateurs should be
there to help Australia as it staggers
down the road to Mr Keating's Clever
Country. Raising fees won't help to en¬
courage our youth into technology via
Amateur radio.
Notice that I have not mentioned those
old chestnuts, Civil Emergencies and
message handling. The SMA will never
be permitted to take these aspects of
Amateur radio into account when deter¬
mining fee structure. For any Official
Body to admit that its preparedness for
emergencies was partly dependent on
the good-will of radio Amateurs would
be tantamount to admitting negligence
in their planning, ergo, it couldn't hap¬
pen. Incidentally, the term Disaster
Planning is an oxymoron. Check out
‘disaster'in the Macquarie Dictionary.
In summary:
The Government, through its SMA,
should be encouraging its citizens to mi¬
grate to the Clever Country by supplying
them with the necessary tickets. Amateur
Radio is one of those tickets and should
be given out free of charge.
As you can see, Dr Kelly came up
with quite a few constructive points. He
still seeks to minimise the spectrum
space allocated to amateurs on a primary
basis, and probably takes the ‘National
Parks’ analogy a little too far, but other¬
wise I can agree with quite a lot of what
he says.
Just for the record, though, I haven’t
written a single prize-winning novel, nor
have I any patents to my name. You have
me there, Dr Kelly, although the rele¬
vance of these points to the current dis¬
cussion escapes me.
Quoted in Parliament
Now before I show you the remaining
missives, I should perhaps note here that
the real hate mail didn’t really start to
arrive until there was a further develop¬
ment. On March 9th, a few sections
from my March editorial were quoted in
Federal Parliament by the Member for
Capricornia, Ms Marjorie Henzell, dur¬
ing a debate on the Radiocommunica¬
tions (Transmitter Licence Tax)
Amendment Bill 1994.
Perhaps it was sheer coincidence, but
one of the sections quoted was — you
guessed it — the bit about licence fees
not having risen for about 10 years. And
as Ms Henzell was using this in a speech
arguing in favour of the proposed rise in
amateur licence fees, this really made
my critics upset.
Here’s a little fax that turned up soon
after from Richard Murnane VK2SKY,
of Dee Why in NSW:
Well, Jim, I hope you're happy... I see,
from the Hansard for 8 March, that your
ludicrous editorial assertion, that Ama¬
teur licence fees haven't gone up in the
last ten years, has been passed off as
fact in the Federal parliament.
I fully expect you to publish a full re¬
traction of your false claim, and to en¬
sure that such retraction is voiced in
parliament when the debate on the ra¬
diocommunications amendment bill res¬
umes in a few days time, or I like
many others I expect — will not be buy¬
ing your magazine in the future.
As you can see Mr Murnane was again
brief and to the point, although how he
expected me to ensure that any retraction
of mine was voiced in Parliament, I’m
not sure. Presumably since I have no
power to control Parliament, we ve now
lost him as a buyer of the magazine...
Here’s another fax along similar lines,
which came from Mr Doug Rickard
VK4ZDR of Upper Coomera, in
Queensland:
/ have previously (22-Feb-1995) reg¬
istered my disappointment with the in¬
correct and misinformed editorial
which appeared in the March 1995
Electronics Australia.
Now that your misleading editorial
has been used in Federal Parliament to
support the SMA case against amateurs,
I hope you are satisfied.
All alone, and in one stroke, you have
done more to damage amateur radio in
Australia than has happened in the pre¬
vious 50 years. In one go you have
erased all the good work that the maga-
42
zinc and its predecessors have done for
decades towards amateur radio. I hope
you are now happy. It might now be an
appropriate time for you to tender your
resignation before you do any more
damage to our cause.
As you can see, Mr Rickard goes
somewhat further than many others, and
was probably the first to suggest that I
should resign. Note that like many of the
other critics, Mr Rickard also uses the
phrase ‘the SMA case against amateurs’
— with its implication that the SMA has
somehow been deliberately targeting ra¬
dio amateurs. There’s no evidence for
this at all, of course; in reality, it’s clear
that the people in the SMA have merely
been doing the job they’ve been given
by the Government, on our behalf.
Even longer bow...
Moving on again, though, here’s an ex¬
ample of a letter which went somewhat
further that those before it, and drew and
even longer bow with its accusations. It
came from Mr R.J. Robinson-Pedder,
VK4BBA, of Currimundi in Queensland:
Being a customer of Electronics Aus¬
tralia for some years now, I was ex¬
tremely disappointed in your very biased
editorial on the massive increases in
TAX to the radio amateur licence fees by
the SMA. The only country in the world
to do so.
Everyone has the right to their own
opinion, including you, but it is all too
apparent that you have been brain¬
washed by the SMA by publishing inac¬
curate data, which you have succeeded
in spreading further. Even into the house
of Representatives. Gee whizz you must
be feeling real proud. What a pity you
didn't get your facts right... Ho hum!
What else could one expect these days
from the media.
May I suggest that before you again put
pen to paper, make sure you have all your
facts right, sunny Jim, before you go to
press. Not to print a whole lot of propa¬
ganda doled out by a very inefficient de¬
partment such as the SMA who are trying
desperately to save face and credibility.
If you believe every word the SMA ut¬
ters as gospel then you must be pretty
gullible. Your article is typical of the
chequebook journalism we are plagued
with in Australia and the rest of the
world these days. Perhaps you are trying
to make a name for yourself. Rest as¬
sured you sure have done that within the
amateur fraternity. So be a good boy, go
back and get all your facts right. Then
go to press. The rest of the amateur
world here in Australia need you and
your magazine like a hole in the head. A
term which was once coined during
WWII was QUISLIN [sic], which seems
to be very apt.
For instance you stated that amateur
licence fees have not risen in ten years.
Wrong!
1995 $37 1990 $34 1986 $23
1994 $36 1989 $32 1985 $21
1993 $35 1988 $28 1984 $19
1992 $35 1987 $26 1983 $19
It is easy to see the fees have increased
faster than the CPI...
Your editorial was also incorrect in
stating that there had been ‘Prolonged
negotiations between the WIA and the
SMA and that the new structure and fees
had been whittled back \ Not so. Ask
anyone other that the SMA and you will
get a different story. Try for starters ask¬
ing the WIA about the prolonged talks...
Your comments in respect to the
amount of spectrum space amateurs
have access to in Australia is very mis¬
leading. May I point out that the major¬
ity of them are on a secondary basis and
only ours until the big boys with pots of
money decide to take them off us... The
multi combines such as Telecom, and all
branches of the media can of course
increase their charges to offset any tax
the SMA place on them. Who do you
think will pay for those increases? In
the long run the general public and see¬
ing that us mere amateurs fail into this
category, we pay again. Great idea ac¬
cording to your philosophy.
If you take time and do some calcula¬
tions sunny Jim, you will end up with a
figure around the 20.5% of frequencies
allocated to amateurs, which are on a
primary basis. Also, you will find that
from 1.8MHz to 14MHz the primary fre¬
quencies for amateurs evaluates to ap¬
proximately 6.1%. This can be further
reduced due to the unwanted 1.7MHz at
28MHz to 29.7MHz.
Furthermore your comments on what
is happening in other countries is true
regarding the big commercial boys hav¬
ing to pay more for what they use. As I
have said before they can redress the is¬
sue by obtaining lots of lucre from ad¬
vertising, or by increasing their charges
to users of their systems. This is not true
in respects of all amateurs, even a novice
knows that your licence does does not
allow you to do so.
For myself 1 have held an amateur ra¬
dio licence for nigh on forty years, hav¬
ing held the calls G3NEE and MP4BA
and now currently VK4BBA. During my
working life, I have been employed in the
radio and telecommunications industry,
as well as the aircraft industry. Here I
worked on such projects as Concorde,
Tornados, Hawks (not the Bob type),
Bal46, Air Bus, Shuttle and satellite
navigational systems. As an amateur I
have been able to contribute many ideas
into these industries and projects. In fact
amateurs were encouraged into these in¬
dustries in the UK. In British Aerospace
there were over 200 amateurs employed
in that industry alone.
We are constantly told by a certain
gentleman in high places that Australia
is the cleaver [sic] country. So clever
that he puts a TAX on amateurs.
Being a returned serviceman, may I
also point out to you that there are many
of us who are on a very limited budget
nowadays. Many amateurs here in Aus¬
tralia, as well as overseas, are invalid,
some are even blind. How do you think
they will cope with this massive TAX on
their hobby, sonny Jim? Many will just
have to give it away. Do you think that is
fair ? Or will it, as in your case, be *Hard
luck Jack, I'm alright... 9
Now come on, sunny Jim. Do the right
thing. Go back to the keyboard, obtain
all the correct facts. Take a deep breath
and then write another epic. This time
make it a retraction and try to put the
score right.
I for one will be 'OUTING* from your
magazine. You can bet your bottom dol¬
lar that 1 will not be the only amateur to
do so after your editorial... Perhaps with
luck your boss will see the errors of your
ways. Now there is something for you to
think about.
Well, Mr Robinson-Pedder didn’t hold
back much, did he? He didn’t quite get
the spelling right, but I’m likened to the
despised ‘quislings’ who sided with their
country’s enemies during WW2. And for
good measure, I’m accused of being
heartless and uncaring about amateurs
who may be blind or infirm, and now
unable to pay their amateur licence fee.
I found this all pretty insulting and
over the top, I must confess. However I
did get a chuckle from Mr Robinson-
Pedder’s other inadvertent spelling error
— the one about Australia being the
‘cleaver’ country. In view of his own
hatchet job on me, the term seems rather
appropriate...
Incidentally you may have noted that
like Mr McGhie, Mr Robinson-Pedder
also describes the 28 - 29.7MHz amateur
band as being ‘unwanted’. I wonder if
all amateurs would take that view, and
would be happy for hams to lose that
band? I would have thought that this
spectrum segment would have signifi¬
cant value for anyone involved in seri¬
ous investigations into propagation, but
perhaps I’m wrong here too.
ELECTRONICS Australia, June 1995
43
FORUM
Letters to Federal’s GM
Moving on again, though, here’s a pair
of letters that in many ways took the
prize for escalating the level of personal
abuse right over the top. They both came
in the one envelope from Mervyn V.
Millar, VK5MX, of Croydon Park in
South Australia, who directed them in¬
itially to the general manager of EA‘s
owner, Federal Publishing Company.
Here’s Mr Millar’s first letter, directed
specifically to the GM:
Dear Sir or Madam,
Please find (Enclosed) a copy of a let¬
ter sent to the Managing Editor of Elec¬
tronics Australia, Jamie Rowe.
I am one of many who are deplored at
the attitude of this ‘EDITOR’ although
he is entitled to HIS opinion he at
LEAST wants to get his FACTS RIGHT
Before shooting his mouth OFF.
This is NOT the first time EA has put
out erroneous and MISLEADING IN¬
FORMATION. Space did not allow me to
go into the other details of his editorials
which were also disputed, and I know of a
number of other Amateurs who have writ¬
ten to him about the same editorial/s.
Rowe should be severely reprimanded
or removed from the position of Manag¬
ing Editor in the same way you removed
another employee (last year) for finan¬
cial mismanagement, because this is
JOURNALISTIC Mismanagement.
As you can see, in this letter Mr Millar
was basically just seeking my removal.
(By the way, the General Manager was
mystified by that cryptic reference to
someone who had supposedly been re¬
moved’ last year, for ‘financial misman¬
agement’. I found it pretty puzzling,
too.) But he became rather less pleasant
in the second letter, which was directed
more or less at me:
It was with much DISPLEASURE I
read your disgusting Editorial in March
EA. Firstly I have been an Operator for
the past (17) Seventeen years. In that
time the fees have RISEN steadily at an
average of$l - $3 per year.
As I recollect my first licence was
around $4 and a friend of mine used to
pay 2/6 pence in the days before the
1939/45 war.
I suppose you have a SALARY in the
range of $50,000 to $150,000/year, so
YOU would NOT miss the rises IF in fact
you had a call sign. (ZLO? - Can't do the
Morse???)
Most AMATEUR Radio operators grew
up with Electronics Australia during the
ELECTRONICS Australia, June 1995
I940’s to 1980’s under the expert help
and guidance of a predecessor of yours,
Mr JOHN MOYLE did you know him?
Rest assured I will NOT be subscrib¬
ing to EA in the future, nor will I buy it
in the shop. Like all small businesses you
forget where your beginnings were, like
many other small businesses, you’ll get
so big and big headed you’ll eventually
go BROKE. Remember it's those little
experimenters and hams that have put
EA on the MAP.
I wonder if you are related to [name
deleted] and if you get your information
from him or does he get his information
from you? Both of you dribble Bullshit
very easily. How about the time you were
plugging EA subscriptions, promising
loads of NEW IDEAS Ham radio, NEW
staff etc. Great magazine, you said. My
how the High and Mighty Jim Rowe
Magazine has fallen to the lowest depth.
I’m Jim Rowe, Wealthy, Healthy &
Wise. I’ll NEVER need anything... One
never knows look at Elliot, Skase, Bond,
WAinc, EtAl.
C U Next Tuesday when you get the
old foot out of the MO UTH.
Hmmm — as you can see, Mr Millar
became rather excited there for a while. So
much so that he lost me in places, like that
crack at the end about ‘next Tuesday’. I
half expected him to appear on die day
with a shotgun, but mercifully he didn’t...
By the way, the person whose name
I’ve deleted (to avoid any possible legal
repercussions) is neither related to me
nor even known to me, so it’s presum¬
ably just someone else who has aroused
Mr Millar’s ire.
To set the record straight, and although
none of these points is relevant, here are
the answers to some of his questions:
(a) Yes, I do have the callsign VK2ZLO;
(b) Indeed, I couldn’t pass the Morse
test; and
(c) No, I didn’t know John Moyle. I
would have liked to have met him, but
unfortunately he was terminally ill in
hospital when I joined the magazine as a
very junior staff member in early 1960,
and died soon after.
I see that Mr Millar believes I’m in the
same league as some of the former high¬
flying entrepreneurs he quotes, presum¬
ably because of my supposed high
salary. Perhaps if this were true (it isn’t,
of course), his allegations might have
been less hurtful than they were...
Final sample
To draw this month’s airing of my
claimed transgressions to a close, here is
the follow-up letter that turned up from
my original critic Will McGhie VK6UU,
following the speech made by Ms Hen-
zell in Parliament:
I have just finished listening to the de¬
bate in Parliament over the SMA’s in¬
crease in licence costs to Amateur Radio
operators. You may be interested to
know that your name was mentioned
several times by the Government spokes¬
person, in relation to the March edito¬
rial you wrote.
The whole editorial was read in vari¬
ous parts and you were portrayed as be¬
ing in support of the Government’s
position that the increases where justi¬
fied. It is unfortunate the misinformation
that was contained in your editorial was
used by the Government as statements of
fact! In particular the ‘no increase in
amateur licence fees in the last 10 years .
Your lack of good journalism has done
the amateur fraternity considerable dam¬
age. I would ask you to write to the Gov¬
ernment spokesperson who used your
editorial as supporting facts’ and inform
her that your information is incorrect.
This misinformation trail has gone full
circle from SMA, to you, to the Parlia¬
ment. 1 will be writing to her to inform
her of the errors in fact in your editorial.
I tried to contact you by phone but you
failed to return my call. This letter has
also been circulated via the Amateur
Radio Packet network, and a copy sent
to the WIA.
As you can see, while still relatively
calm Mr McGhie was now also claiming
that I had done considerable damage to
the amateur radio ‘fraternity’ (which
seems a particularly ironic term, in view
of the actions of many of his col¬
leagues). There also seems to be an im¬
plication that I was somehow linked in a
conspiracy to disseminate misleading
information, which is quite false.
Perhaps I should note here that once I
had learned of the errors of fact in my
March editorial, I immediately arranged
to publish a correction in the next avail¬
able issue — which happened to be
May, as the April issue had already been
printed. As this correction would not be
published until well after the debate in
Parliament was due to be resumed in
late March, I also decided to sent letters
advising of my errors to both Ms Hen-
zell and Senator Alston, the Opposition
spokesman for Communications.
Copies of these letters were supplied to
the President of the NSW Division of the
WIA, Mr Michael Corbin VK2PFQ, and
Mr Corbin read them out during the Divi¬
sion’s Sunday morning broadcast of
March 19, to inform his listeners of my
efforts to compensate for any damage
(Continued on page 73)
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READER INFO NO. 15
THE SERVICEMAN 1
•
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--- 1
The car that produced wow
and flutter in cassette players!
Since stories about generators and alternators seem to be quite popular, I’m presenting a couple
more for your edification this month. One concerns a simple, but surprisingly hard to track down
problem in a car, which made it produce wow and flutter in two different radio cassette players. The
other is about a diesel generator set that wouldn’t start...
One of the items in last November’s
column, about the old Volkswagen with
the reversed battery polarity, has
generated (no pun intended) a steady
stream of stories about generators, alter¬
nators and general automotive electrical
subjects. This month we continue the
subject with a story from Keith Walters,
of Lane Cove in NSW. Keith’s tale is
about a queer problem that took him
something like eight years to solve, and
is still showing up in other vehicles,
some 20 years later!
Here is what he has to say...
We've all encountered the situation
where, after hours, days or even weeks
of our fruitless toiling over an obscure
faulty some smart-alec wanders in,
casually points to something ap¬
parently totally unrelated and says: “It's
that!" And as often as not f it *#$%?@H-
well IS 'that', too! An honest smart-alec
(or one who knows what's good for him)
should of course have the decency to
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reveal how long it took HIM originally
to find the fault!
My personal favourite story in this
vein was a former colleague who, many
years ago, had been struggling with a
Thorn 3504 colour TV, off and on for
some weeks. This model was actually the
old British 3500 chassis, modified for
Australian conditions by fitting a power
transformer and a VHF turret tuner.
Unfortunately they didn't do a very
good job — the sets were prone to in¬
stability on channel 'O'. There was
some sort of regeneration effect that
narrowed the IF bandwidth to the point
where colour and sound couldn't be
obtained at the same time. In extreme
cases it would go into oscillation,
blacking out the screen.
Anyway, I'd moved to another city
about a year before this, and he'd men¬
tioned the problem as a aside on a
Christmas card he sent me. ('That
@?#?*H 3504 is still driving us up the
wall, etc. etc.') So by return mail, I put
him out of his misery.
The secret was that Thorn seemed to
be very partial to using a particular
type of free standing air-cored induc¬
tor, using some sort of fabric-covered
wire treated with wax so that the turns
didn't unravel. (Old hands will know
the ones I mean). There was one of
these mounted on top of the tuner. All
you had to do was twist it around 90
degrees and all the faults would disap¬
pear! (So how long did it take ME to
find that one first time? Don't ask...)
There are many other stories: The dry
joint on the chassis heater connection on
old Admiral valve sets, that made
EVERYTHING crook; the thick-film
module in the Thorn 4KA vertical board
that caused poor horizontal hold while
not affecting the vertical circuit in any
way at all; 'No picture' on the same
chassis, caused by a slug falling out of ti
coil on the EHT regulator and getting it¬
self lost; the 4.7uF electro on the CRT
base board of numerous Sanyo models,
causing a dark picture — I'm sure you
all have your favourites.
Baffling fault
Anyway, recently I was able to help a
non-technical friend with a baffling
fault in his car. While he was greatly
impressed by the way I was able to
identify the problem straight off
(without even seeing the vehicle!!), I
had to admit that it had taken me the
best part of EIGHT YEARS to do the
same for my own car! (I won't tell you
what his problem was straight off —
see if you can work it out...)
It all started nearly 20 years ago,
when I worked for a well-known
electronics service company. They were
having a clean out in the radio workshop
and I was given a faulty car radio-cas¬
sette unit that had been an unacceptable
quote and was never collected.
Now in those days, car radio-casset¬
tes were still relatively uncommon and
quite expensive, so I was surprised to
find that all it seemed to need were
new output transistors. Two
BD237/238 pairs were promptly fitted
and that seemed to be that.
It was a reasonably up-market unit,
with proper locking fast forward and
rewind (in those days a lot of them just
had a non-locking 'slightly faster' for¬
ward). The tuner was admittedly a bit of
a weirdo — it had two bands: one AM of
course, and one SHORTWAVE band!
Why they thought anyone would want
to listen to shortwave while travelling in
a car was beyond me, unless it was so
that less-informed purchasers might mis¬
take it for a more expensive to build
AM/FM unit! (There were no FM broad¬
casts in Australia at the time, so they
wouldn't have been any the wiser).
46
ELECTRONICS Australia, June 1995
Anyway, all this is just by way of
saying that it was quite a respectable
unit, certainly worth spending a bit of
time and money on. Which was why I
was surprised that the original owner
hadn't accepted the fairly modest quote.
The radio worked well (even on
shortwave!) and with a pair of 6"x 9”
speakers mounted in the back of my
Fairmont station wagon, gave what
was for those days a really impres¬
sive performance.
Unfortunately the cassette unit was
less successful. It worked OK on
the bench and when the car was sta¬
tionary, but developed moderate
(sometimes severe) wow and flutter
when the car was in motion. I was able
to source some replacement rubber
components, but these didn't seem to
make much difference.
It wasn't all THAT bad — on sealed
roads the problem was often barely
noticeable, but it could be really annoy¬
ing on bumpy roads. I was beginning to
suspect that the original owner mightn't
have been so silly after all.
I put up with it for about five years,
then when FM broadcasts started I
replaced it with a new radio-cassette
(with a REAL FM band!). The old one I
gave to an impecunious acquaintance, to
put in his work truck.
Alas, although the cassette player in
the new unit was a considerable im¬
provement over the old one, it STILL
produced noticeable wow and flutter.
Even worse, the old one now per¬
formed faultlessly in its new loca¬
tion, despite the truck's rough and
ready suspension (and the driving
skills of its owner).
I wondered if there might have been
something wrong with my battery volt¬
age, although there was never any
trouble starting. The voltage certainly
measured OK when the car was idling,
and I never got round to trying the more
complicated hookup needed to test it on
the road.
Then one year I was given a dash¬
mounting ammeter/voltmeter unit, for a
birthday present. I duly installed it (it
simply connected to the battery ter¬
minals), and driving over a bumpy road
for a while showed nothing amiss.
(There's a clue in there...) Anyway, as I
said, the problem wasn't all that severe,
and as I don't play that many tapes, I
more or less forgot about the tape speed
problem. Then the car itself developed a
peculiar fault.
Normally, once the engine had
warmed up, the temperature gauge
would sit at about half-scale and never
move from there. But suddenly it started
indicating an abnormally high tempera¬
ture — although only when the car was
moving. Once the car was stationary
again, after about 20 seconds the read¬
ing would return to normal.
In the abnormal state the reading
would climb and fall at a fairly
sedate rate, so I didn't think it was likely
to be some sort of intermittent open or
short circuit.
Older cars often used a simple
mechanical voltage regulator for the
temperature and fuel gauges (maybe
they still do!). This was just a bimetallic
strip with a heater element wrapped
around it, functioning rather like an in¬
dicator flasher unit.
When it was cold, current would flow
through the heater element, which would
UK4B -TW/S
O/vJ.•. Dc*TT
Mind IT..)
/Wow/
uurikRi
eventually cause the bi-metallic strip to
bend and thus break the circuit. It would
then cool down and straighten out again
until the contact was remade and so on.
The effective function was to maintain
the bimetallic strip at a constant average
temperature. The higher the battery volt¬
age, the less time it needed to spend in
the 'on' state to maintain the same
temperature. This switched voltage thus
provided an essentially stabilized power
supply for the hot wire ammeters in the
fuel and temperature gauges.
A common fault in early model Fal¬
cons was that the heater wire would go
open-circuit, eliminating the regulating
function and so making the gauges read
maximum all the time. I seemed to
remember the term five volt regulator'
being mentioned somewhere, so I tried
replacing the mechanical unit with a
7805 IC. The fuel gauge then worked
perfectly, so I knew that the voltage was
correct. Unfortunately it had no effect
whatever on the strange behaviour of the
temperature gauge.
Localised heating?
The problem I faced was this: WAS it
just a gauge malfunction, or was there
some weird condition in the engine that
was causing localised heating around
the temperature sensor? Certainly I
didn't imagine the whole engine could
heat up and cool down that fast, and
there was no sign that it was doing so.
But I wanted to be certain.
Unfortunately the engine was one of
the old 289 cubic inch (4500cc) V8s,
which were not all that common; so
nobody I knew had that much experience
with them. I decided the best approach
would be to remove the temperature sen¬
sor thermistor from the block and
measure its resistance sitting in a pan of
hot water at a known temperature, then
\ compare its resistance when it was fitted
back in the block, in the fault condition.
I can't remember what the actual resis¬
tance was, but as the water heated up, its
resistance seemed to change smoothly
enough and no amount of tapping or
banging could upset it. Then I fitted it
back in the car and went for a drive,
with my digital multimeter connected be¬
tween the sensor wire and earth.
The meter was one of the ‘ Sabtronics'
(USA) kits that were advertised in EA in
the late 1970's. (It's still going strong 17
years on, incidentally!) In these, the
‘ over-range' condition is indicated by
blanking the digits. However, there is a
problem with this sort of indication.
Switched to the ‘ Ohms' range, the
meter will spend most of its time reading
an open circuit (i.e., over-range), so the
digits will be blanked. So that you will
know the unit is switched on, the ‘ Ohms'
reading is always preceded by a minus
sign. This is important in light of what
happened next.
I let the engine warm up for a while,
until the ohms reading seemed to
stabilise, then I drove off. With a sink¬
ing feeling I watched the display. As
soon as I started moving the resistance
began to fall. Down, down, faster and
faster it fell, until it reached zero.
Then, the minus sign disappeared and
it began to climb again! What the...?
A NEGATIVE resistance?
Suddenly the penny dropped.
I switched the meter to the ‘ volts'
range. The engine block was about four
volts NEGATIVE with respect to the
chassis! When I stopped and let the en¬
gine idle for a while, it dropped back to
about half a volt. I got out a jumper
cable and connected it between the en¬
gine block and the chassis. The voltage
ELECTRONICS Australia, June 1995
47
THE SERVICEMAN
dropped to zero. I reconnected
the temperature gauge and sure
enough, after that it worked
perfectly. / drove up to the
local garage, bought a proper
battery cable and made a per¬
manent job of it.
So what was wrong? Well, in
that car, the battery negative is
connected to the engine block,
as are the earth returns of the
ignition and the voltage
regulator/alternator circuitry.
Thus all those systems (and the
starter motor) will have a nice
solid connection to the battery
negative, and if you measure the
battery voltage directly on the battery ter¬
minals, (as the dash-mounted meter did!)
it will be correct.
Unfortunately, everything else in the
car depends on the chassis for the nega¬
tive return. To accommodate this, there s
supposed to be an earthing strap from the
chassis to the engine block — but ob¬
viously at some time in the car’s life, this
had been removed and not replaced.
Any electrical connection between the
battery negative and the chassis was
thus entirely accidental! When the car
was stationary, the block would settle
down and make a satisfactory connec¬
tion; but as soon as I drove off, the con¬
tact would deteriorate.
The 5V regulator would still produce
five volts between the gauge positives
and chassis, so the petrol gauge would
work OK, because the tank sensor is
also connected to the chassis. However,
the temperature sensor is earthed onto
the engine block, so the four volts at
that point would be added to the five
volts from the regulator, giving the
funny’ readings!
Other benefits
Needless to say, once this fault
was corrected the cassette player
magically lost its wow and flutter.
But there was more!
The turn indicator flasher unit
now responded with a brisk
businesslike ‘CLICK-CLICK!
CLICK-CLICK!’, instead of the
weary ‘click...clunk, click...clunk
that I was used to. Also the horn
now produced a mighty roar in¬
stead of its previous strangled
bleat, and the headlights were
noticeably brighter.
It also gave me an explanation
as to why my radiator had rotted
away, after only a few years! The
chassis-earthed radiator would
48 ELECTRONICS Australia, June 1995
iTS sofFSMd 6,. HoT
Ahib Cold SHWERS...
be positive with respect to the engine’s
water jacket, attracting corrosive nega¬
tive ions... f
And my friend’s problem? Well, he d
bought a rather nifty little gadget,
from one of those ‘auto bargain-barn’
places — a suppressed-zero voltmeter
that plugged into the cigarette lighter
socket. A great idea, I would have
thought. Except that it would read the
appropriate ‘13.8V’ when the car was
idling, but (you guessed it) the voltage
would drop alarmingly whenever he
drove off. Yet — the car ALWAYS
started first time every time...
A proper battery strap fixed his prob¬
lem, much sooner than it did mine!
Well, isn’t that something? How many
readers are right now dashing out to
check if their car’s battery strap is cor¬
rectly positioned? I know I did!
Actually I have just such a tempera¬
ture gauge problem as Keith described.
But unfortunately, my trouble is of a
different persuasion, since both volts
and ohms read zero between block and
chassis. I guess I’ll have to seek my
solution elsewhere.
This story had me really baffled, until
M,
, TrfA't'i V-IKKT T.
lC AU,A6oo0S£A^M
frt€ TtMb
Keith revealed the answer
towards the end. However, one
comment earlier in the story
should have prompted the correct
train of thought — he wrote in
the abnormal state, the tempera¬
ture would climb and fall at a fair¬
ly sedate rate.’
This description is a perfect
slow motion allegory of ‘motor
boating’, a common enough prob¬
lem in radios and amplifiers when
power supply (read ‘earth return’)
impedances are upset.
All round, this was quite an in¬
teresting story. I imagine quite a
number of technicians have
chased wow problems in car cassette
players, only to find later that it was a
poor battery connection that was the real
culprit. So although this was an auto
electrics story, it carries a message for
those technicians who dabble in car
sound, and any others who might be con¬
fronted by a poor earth return situation.
Incidentally, and regarding the unusual
coverage of the original radio/cassette,
AM and shortwave, 1 seem to recall read¬
ing in a Clarion (brand) sales manual that
these models were intended for sale in
remote areas of Africa, Asia and South
America. In fact, in some of these places
there are not even any broadcast-band
AM stations, let alone FM ones.
So the inclusion of shortwave reception
makes good sense. Some of these models
may well have been sold in Australia 20
years ago, since at that time we had plen¬
ty of remote areas with no AM stations
and as Keith said, no FM stations in the
settled areas either!
Thanks, Keith. Your story has more
than the usual interest, since it provides
food for thought from quite a number of
different angles.
Genset troubles
Our next story is on a similar
‘internal combustion’ subject,
and again demonstrates the
trouble that our country cousins
have to endure to get the power
that we city dwellers get with the
flick of a switch.
It comes from Peter
Laughton, of Albion Park,
NSW. We’ve heard from Peter
before, with a long and in¬
volved story about home light¬
ing systems. This tale concerns
a similar installation, but with a
different kind of fault. Here’s
his story:
It started out as an urgent call
READER INFO NO. 16
to repair a generator set, at a rather
isolated property near here. It was a
couple of days later before I came face
to face with a 7.5kVA single phase,
50Hz twin-cylinder Lister diesel alter¬
nator set that could not be started,
either remotely or locally.
The owner had jury-rigged several
wires to the starter motor and also the
fuel control solenoid, to enable him to use
the system. This had effectively bypassed
all the engine protection circuitry such as
low oil level, oil pressure, cooling fan
blocked etc. When I opened the control
box I found, as well as the usual contin¬
gent of spiders and other crawly things, a
large control board mounted via lugs to
the switches and lights on the front panel.
While waiting for me to arrive, the
owner had obtained the circuit diagram.
As can be seen, for what it does it's rather
complicated. The first problem was that
the main 12 volt fuse was open, and it
looked like a violent self destruction with
blackened glass inside the tube.
A new fuse was fitted and this held OK.
Now pressing the local start button (PB1)
brought a healthy clunk from the relay
CR, but still no start. There was no output
to terminal PCB3, on the board. The
delay module relay was picking up, as
was the timer for overriding the protec¬
tion upon startup.
With a lot of difficulty, the PCB was
removed from the control box and con¬
nected to a separate variable low voltage
power supply I had brought with me.
The relay CR turned out to be a latch¬
ing type that had two sets of contacts,
which changed state according to a pulse
from pushbutton PB1. A quick check with
the meter showed that the contacts
weren't making properly, and a visual in¬
spection through a rather dirty and faded
plastic case showed some burning of the
faces. Luckily, it was a double pole relay
and the second set of contacts weren't used.
I swapped the wires from the original con¬
tacts to the unused ones, plugged the board
in, and tried a local start.
The starter now turned over, but still
the engine didn't fire — the fuel solenoid
wasn't picking up. (I had removed all the
4 extra wiring that the owner had fitted).
Tracing the wiring to the terminal strip
showed a low and varying voltage at ter¬
minal E2.1 suspected a dry joint, but not
anything like what I really found.
It turned out to be the actual push-on
lug. It was a solder type, and although
the wire was tinned and crimped into the
lug, there was absolutely no trace of
solder! In fact, closer inspection showed
that none of the lugs had ever been
Continued on page 73
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Circuit & Design Ideas
Oil temperature indicator
This circuit is basically a thermometer
that uses a negative temperature coef¬
ficient thermistor. The thermistor used
in the circuit is a VDO Instruments
probe and comes with enough
hardware to install it in place of a
dipstick. The thermistor is in the tip, and
the probe can be bent sufficiently to fit
inside transmission dipstick housings.
Obviously the connections to the probe
need to be disconnected before using the
probe as a dipstick.
The circuit gives a visual warning that
the oil temperature in a transmission or
sump is exceeding a certain value. This is
usually a better indication of engine
temperature than that given by the water
temperature gauge.
The thermistor is supplied with a con¬
stant current of 5mA, developed by
Q1 in conjunction with ZD2, R3, R2
and RV1. Because the base of Q1 is
held at a constant voltage by ZD2, the
emitter voltage is also constant, though
higher by 0.6V. This voltage is across R2
and RV1, and RV1 is set to give the re¬
quired 5mA, as indicated by a voltage of
2.35V across R2.
The NTC thermistor (placed in the oil
being monitored) reduces its resistance
with an increase in oil temperature. The
resulting voltage across the thermistor is
applied to ICla, a non-inverting amplifier
with a gain of 19. The output voltage of
ICla is then fed to the rest of the circuit
to drive a meter (optional), or operate
various LEDs.
IClb and IClc are comparators that
sense the output voltage from ICla. The
trigger voltage for each comparator is set
by the potential divider comprising R9 to
R12. If you are using this circuit with a
high-performance engine and high-
temperature engine oils, increase the
value of R9 to 18k. Otherwise, select a
value for R9 to suit. For the thermistor
shown, a value of 8.2k for R9 will cause
the output of IClc to go high for an oil
temperature of 117°C. This extinguishes
LED2 and enables the oscillator around
ICld, in turn operating Q3 which flashes
LED3, giving a warning that the oil
temperature is exceeding this level.
Increasing the value of R9 increases
the temperature level at which com¬
parator IClc responds. As a general rule,
at an oil temperature of 130° you have
just enough time to get clear of traffic and
park. An oil temperature of 80°C causes
acid build-up to start boiling off.
The prototype was built on strip board
and housed in a small jiffy box fixed to
the dashboard with double-sided tape. A
variation might include using two ther¬
mistors. By selecting either one with a
switch, the circuit can monitor both en¬
gine and transmission temperature.
To calibrate the circuit, use a 100 ohm
0.5W resistor in place of the thermistor
and adjust RV1 (a 10-tum pot) to give
2.35V across R2 (or 5mA of current in
R2. Have the engine running to give a
supply voltage of at least 13V. As a
double check, turn the engine off,
recheck the 2.35V across R2, then check
that the output of ICla is 6.46V, +1-2%.
To confirm that the oscillator starts at an
oil temperature of 125°, substitute a 47
ohm resistor for the thermistor. The out¬
put voltage of ICla should be 4.46, +/-
2 %.
Peter Lucock,
Wynnum West, Qld. $40
EVER THOUGHT OF WRITING FOR EA?
Have you developed the circuit of the century, or
a really great design, and would like to tell others
about it? Have you written the best article ever on
electronics theory or practice? Either way, you
probably can’t wait to see your work published as
widely as possible.
Get your achievements to the largest number of
your colleagues and fellow enthusiasts, and make
some money at the same time, by sending your ar¬
ticle to the Managing Editor of Electronics Australia,
PO Box 199, Alexandria 2015.
If you’re not sure just how to write your article,
ring our office on (02) 353 0620 and ask for a copy of
our writer’s guide notes.
50
ELECTRONICS Australia. June 1995
Stable 100kHz source
I needed a very stable sinewave source for alignment of a
multi-section crystal filter, which forms the heart of a commer¬
cial wave analyser. The source needed to be a stable 100kHz,
+/-lHz sinewave, variable by +/-5Hz.
An 8MHz crystal oscillator is formed by XTAL1 and IC1.
Frequency adjustment is provided by variable capacitor C2. IC2
is a binary divider and IC3 is a decade divider. The network
consisting of LI, C3, C4, R2 and R3 filters out anything above
the second harmonic, giving a relatively pure 100kHz sinewave
with excellent stability and variable frequency. By selecting dif¬
ferent outputs from IC2 you can also get 50kHz, 200kHz and
400kHz outputs. However the values of C3 and C4 need to be
changed to suit. Note that 4000 series CMOS ICs running at 5V
have a maximum frequency of around 3MHz, so they are only
suitable as a divider in this circuit.
Braham Bloom,
Russell Lea, NSW. $35
Flashing beacon
This circuit was designed after seeing
an advertisement in an American
magazine for a programmable beacon,
with an output of about 700mCd
provided by what appeared to
be three LEDs.
It consists of a 555 timer running in as-
table mode at about 1Hz. This clocks a
4017 decade counter/divider with outputs
0 to 7 going high for one second each in a
continuous loop, since the reset pin (15)
is connected to output eight (pin 9).
Each output is connected to the base of
Q1 via an isolating diode (D1 - D8) and a
switch (DIP SW 1-8). Transistor Ql, R4,
D8 and D9 form a constant current
source for the LED. The current is 0.65
divided by the value of R4. Various flash
patterns are possible, depending on the
setting of the switches. For instance, one
second on, then seven seconds off, or
four seconds on and four seconds off.
I used a 3000mCd LED (available
from Jay car) operating at a current of
20mA. For best light output, use two or
three LEDs in series, depending on the
supply voltage.
Michael Sampson,
Tamworth, NSW. $35
Energy monitor
Living with alternative energy (hydro
and solar power) means it’s often neces¬
sary to measure power consumption, to
ensure that power inverters and gener¬
ators are not overloaded. The measure¬
ment of energy consumption of
individual appliances is also needed to
calculate the amount of battery storage
needed, as well as charging options etc.
The measurement of power con¬
sumption is straightforward using a
moving iron ammeter (giving a true
RMS response to the waveform of an in¬
verter). However, the measurement of
energy consumption involves time and
isn’t so easy.
This circuit is a very simple way of
measuring energy consumption. A trans¬
former is connected as a current trans¬
former and supplies power to an hour run
meter, a Warburton-Franki type obtained
from Oatley Electronics for $15. This
device is similar to the odometer of a car,
in that it registers time on a number of
wheels, to 0.01 of an hour. It operates
only while power is applied, so the length
of time an appliance consumes energy
over a given period is recorded.
I used a transformer designed for a
Scope soldering iron. However, the
secondary voltage rating can be between
AQ
N O-
EO-
3.3V winding
Uju
-O A
jrrrn
o
3.3:240V
transformer
hour
run
meter
-O N
-OE
> to appliance
three and 12 volts, as this rating only af¬
fects the lowest power the hour meter
will respond to. The current rating of this
winding should equal or exceed the full
load current being measured. A
refrigerator draws around 300 watts or
1.2A at 240 volts, so the winding must be
able to carry that current.
Be careful if running the transformer
without a load connected to the 240 volt
winding, as a high voltage can be
developed (more than lkV in some
cases). If using a multi-tap transformer,
such as from an old radio or TV, ter¬
minate the unused windings with a
suitably rated load resistor. By using this
device you can check the energy ratings
of appliances and compare it to the pub¬
lished rating. The prototype responded to
a minimum power of 30 watts or so.
Peter Laughton,
Albion Park, NSW. $30
ELECTRONICS Australia, June 1995
51
DICKMSMITH
ELECTRONICS
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DSE ‘Discovery Series’ Construction Project:
PARMIH PORT INTERFACE
SsSsseSsis
as Cat. No. K-2805, priced at $42.50.
If you are a creative person with a
computer, then there’s sure to be some
project at home or work that could use
this project. It acts as a ‘real world inter¬
face for your computer, allowing it to
directly sense data, process it and use the
results to directly control — rather than
just processing data fed in manually.
In combination with readily available
transducers (sensors) the computer can
monitor physical parameters such as
temperature, pressure, movement, light
intensity, etc, process the information and
then control physical things using relays,
solenoids, motors and so on.
The interface works via a standard
Centronics (parallel) printer port and,
because of its low power consumption,
can be operated from a 9V battery (not
included in the DSE kit) or any DC
supply in the range 7.5-25V. It can
monitor 10 analog voltages, drive eight
digital outputs and generate two variable
analog voltages. It can also read its own
power supply voltage, to make possible
‘low battery’ warnings, and the power
supply can even be switched on and off
by the computer.
Sample programs are provided which
allow you to control the interface imme¬
diately. You can expand the programs
later to suit your own needs.
Connection to the interface is made
easy by PCB mounted plugs and sockets,
which are provided in the DSE kit. A 25
pin male ‘D’ to 25 pin male D connect¬
ing cable, preferably a shielded type, is
required for connection to the computer
printer port. The kit PCB is designed to
fit in a Dick Smith Electronics ‘Zippy’
box Cat. No. H-2851. The printer cable
and box are not provided with the kit.
The interface circuit can be divided
into a number of functional blocks.
There is a 24-bit shift register/latch,
consisting of IC’s 1-3, which receives
three eight-but bytes of data from the
computer and holds it for controlling
the interface outputs.
Two of these bytes, stored in IC1 and
54 ELECTRONICS Australia, June 1995
IC2, are used to drive a pair of digital to
analog converters (DAC’s) which convert
this data into analog voltages at analog
output terminals 0 (SK3) and 1 (SK2)
respectively. The third output data byte,
stored in IC3, is fed to buffer IC5 which
allows each bit to control one of eight
high current digital outputs available at
connector SK4.
The analog input circuitry is based
around IC4. This is an analog-to-digital
converter (ADC) with 12 addressible in¬
puts (AO - All), and serial interfacing on
the digital side.
The computer is therefore able to in¬
struct the ADC chip (via pin 17) regard¬
ing which of the analog inputs is to be
selected, after which the ADC performs a
conversion and signals the computer that
the digital data is ready, via the EOC out¬
put. The computer can then retrieve the
data serially from pin 16.
Note that 10 of the external analog in¬
puts of IC4 are used for the analog inputs
of the interface, while the final external
input (A10) is used to allow the computer
to monitor the interface’s own battery
voltage via resistive divider R65/R66.
The twelfth input is connected internally,
as described later.
The printer port
Before describing the functional blocks
in more detail, it helps to know how the
Centronics printer port is controlled. The
port has 25 lines, some of which are for
signals and others for ground or signal
return paths. The signal lines are either
read-only (input to the computer) or
write-only (output from the computer)
and use 5V (CMOS or TTL) logic.
In the computer, three addresses in I/O
space are required to completely access
the printer port. The first address is called
the base address which is usually 378
(hex) for printer port 1 (LPT1) or 278H
for LPT2.
The second address is (base address
:
Table 1
Printer Port Wire Allocations
Address
Bit
Wire
Direction
Kit Function
Printer Function
base
0
2
write
IC1 serial data input
Data bit 0
base
1
3
write
IC1 - 4 Clock
Data bit 1
base
2
4
write
Load IC1 latch
Data bit 2
base
3
5
write
Load IC2 latch
Data bit 3
base
4
6
write
Load IC3 latch
Data bit 4
base
5
7
write
IC4 chip select(-)
Data bit 5
base
6
8
write
IC4 address input
Data bit 6
base
7
9
write
Power on
Data bit 7
base+1
3
15
read
not used
Fault(-)
base+1
4
13
read
IC4 data out
Select
base+1
5
12
read
not used
Paper empty
base+1
6
10
read
IC4 end of conversion
Ack.(-)
base+1
7(-)
11
read
busy
not used
base+2
o(-)
1
write
IC1 output enable(-)
Strobe(-)
base+2
l(-)
14
write
IC2 output enable(-)
Auto feed(-)
base+2
2
16
write
not used
Init.(-)
base+2
3(-)
17
write
IC3 output enable(-)
Select In.(-)
18-25
OV
OV
NOTES:
1. Normal base addresses
are;
LPT1 = 378H
LPT2 = 278H
2. (-) next to the bit no. means if the bit is set to 0 then the wire is at +5V.
3. (-) next to the function means the function is activated by OV.
+ 1) and the third address is (base address
+ 2). At each of the three addresses there
is an eight bit byte stored, with bit 0
being the least significant bit (LSB) and
bit 7 the most significant (MSB).
Every signal line on the port, whether it
is used for read/input or write/output, is
allocated one particular bit at one of these
three addresses, the logic state of the bit
indicating the state of the wire (0 or
+5V). A few of the lines use negative
logic — i.e. logic 1 corresponds to 0V
and logic 0 to +5V. Table 1 shows the
significant bits at each of the three ad¬
dresses, and the functions these are used
for, both normally when the port is used
to communicate with a printer and in
when it is communicating with the inter¬
face described here.
As an example of how the interface is
controlled from a program written in
QBASIC, the following short command
sequence is used to switch the power on
and enable the output of IC1:
BASEO = &H378
OUT BASEO, &H80
OUT BASEO + 2, &H01
Here the first line defines the base ad¬
dress of the printer port, as 378H. The
second line then sends 80H (binary value
= 10000000) to base address 378H,
which sets data bit 7 of the port and
switches the interface’s power on. The
third line then sends 01H (binary value
00000001) to address 37AH (base+2),
which sets bit 0 of this data byte. As you
can see from Table 1 this causes Strobe
line 1 to be taken to 0V, as this line uses
negative logic. However this line is ac¬
tually used to enable pin 13 of IC4,
which is an active-low input — so the
desired effect is achieved.
The printer port output data is stored in
latches, so the commands do not have to
be repeated to keep any wire in a par¬
ticular state.
Input conditioning
The devices in the computer that drive
the printer port outputs may be either
TTL or CMOS IC’s. CMOS devices,
such as this interface uses, cannot be
directly driven (reliably) from TTL out¬
puts because the logic 1 output voltage of
a TTL device can sometimes be lower
than the logic 1 input voltage required by
CMOS devices.
In this project, this is avoided by ad¬
ding ‘pull-up’ resistors R12-19 to the in¬
terface inputs, to ensure that the input
voltages fall within the acceptable CMOS
input range.
Another problem which has to be al¬
lowed for is that the cable connecting the
printer port to the interface may pick up
interference, especially if it is unshielded
or running close to some strong
electrical interference. The sort of
noise that is likely to cause problems are
short duration voltage spikes from arcing
electrical contacts of equipment con¬
nected to the mains.
To suppress these spikes, series resis¬
tors R2-11 and shunt capacitors C2-11
have been added. An adverse effect of
this sort of suppression is that it slows
down the rate at which the wanted signals
can change, by about 200ns. This effect
can be ignored when using BASIC
programs, and in any case it can be com¬
pensated for by providing suitable pro¬
gram delays.
Interface details
For the control of so many inputs and
outputs, the interface designer chose to
use serial rather than parallel data transfer
between the computer and the interface
board. Serial data transfer requires less
wiring, less hardware and consequently
less PCB space.
Data from the printer port to control the
10 interface outputs (analog outputs 0/1,
and digital outputs 0-7) is initially loaded
via pin 2 of DB25 connector SK6 into the
series-connected shift registers IC1-3, via
pin 14 of IC1. The eight-bit shift registers
in IC’s 1-3 have their serial inputs at pin
14 and serial outputs at pin 9 (as well as
an eight-bit parallel output), which allows
the three to be connected in series as a
single 24-bit serial in/parallel out shift
register. Data is moved through the shift
registers one bit at a time by clock pulses
applied simultaneously to pin 11 of all
three devices.
The clock inputs are normally held at
0V, and generating a clock pulse involves
applying logic 1 to pin three of the printer
port, and then removing it with the next
command. Delays involved in the proces¬
sor carrying out these instructions nor¬
mally ensure an adequate resulting width
of the clock pulse, or of similarly
generated signals.
The 74HC595 devices used for IC’s 1-
3 contain eight-bit latches. These are
loaded from the parallel outputs of the
shift registers whenever a positive-going
signal is applied to pin 12. Latches are re-
quired in this circuit because if the
DAC’s were fed directly from the shift
registers, then the DAC output would
change erratically as new data was
shifted into the shift registers.
The three latches can be loaded in¬
dividually using separate pulses on port
lines 4, 5 and 6 (SK6), if links J4 and J5
are wired in the 1 - 2 position (as shown
on the circuit). Alternatively they can all
be loaded together from a pulse on line 4
of the port, if these links are fitted in the 2
- 3 position.
The latch outputs of the 74HC595 are
tri-state and can be switched off, i.e..
made open circuit, whenever pin 13 is at
logic 1. This causes the DAC outputs to
go to 0V and the digital outputs to
switch off. This facility is available for
software control if links J1, J2 and J3 are
fitted in the 1-2 position, or can be dis¬
abled by inserted these links in the 2-3
positions instead.
The 74HC595 devices also have a reset
facility. Whenever pin 10 is at logic 0 the
registers are reset to contain all 0’s, while
when this pin is at logic 1 they are free to
accept data.
ELECTRONICS Australia, June 1995
55
DISCOVERY’SERIES PARALLEL PORT INTERFACE
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Although it may look a little complex from the schematic, the interface hardware is relatively straightforward and involves
only a small number of ICs. Chips IC1 to IC4 perform the serial input and output functions.
56
ELECTRONICS Australia, June 1995
In this circuit the reset inputs have all
been connected in such a way that when
the power is applied to the circuit, reset
occurs until Cl charges via Rl. In other
words, the registers are reset during
power-up, but then allowed to accept data
from the PC port.
D-to-A converters
The eight-bit digital to analog conver¬
sion is carried out by resistor networks
R20-35 and R37-52, which are known as
R-2R ‘ladder’ networks because only two
values of resistor are used,
having values in the ratio 1:2.
The analog output voltage
(Vout) is related to the digital
output (N) by the following for¬
mula (Vcc in these formula is
the +5V supply rail voltage, not
the LM358 supply voltage):
Vout = N * Vcc/256
where Vcc is the +5V supply
rail voltage of IC1 and IC2, not
the supply voltage of IC6. So
in this case the output voltage
is approximately equal to:
Vout = N * 20mV
In other words, the output
voltage cannot be varied con¬
tinuously, but in minimum in¬
crements of 20mV. These steps
and any other ‘glitches’ which
may occur at the output of the
DAC network, are rounded off
or filtered out by capacitors Cl2 and
13, and then buffered by unity gain
amplifiers IC6a and IC6b before appear¬
ing at the output terminals. The final
output voltages vary from 0V to +5V,
in 20m V steps.
Before connecting a load to the analog
outputs, it should be noted that the out¬
puts should be used as current sources
rather than as current sinks; i.e., they
work best into a resistive load connected
to ground. The reason for this is that the
LM358 negative supply is at 0V, and the
output voltage cannot reach 0V when
sinking even small currents. Whereas be¬
cause the positive supply is at least 1.5V
above 5V, the outputs can reach 5V for
output currents up to at least 20mA.
Another reason for making supply for
IC6 greater than 5V is that the operating
voltage range for the LM358 inputs is
from 0V to (Vcc-1.5V). The output from
the R-2R resistor network can reach +5V,
and so the positive supply for IC6 has to
be at least 6.5 V.
Digital outputs
The eight output bits from IC3 are
fed to eight separate buffer amplifiers,
all contained within IC5, which is a
ULN2803.
These buffers act as switches con¬
nected between the output and ground,
each using a single stage Darlington tran¬
sistor configuration with an open collec¬
tor output. When the input is at +5V the
switch is on, and when the input is 0V the
switch is off.
To protect the output transistors, the
outputs are all connected via separate
diodes inside the IC to a common point
which appears at pin 10. By connect¬
ing a zener diode between this point
and the IC ground, the voltage at the out¬
puts is prevented from exceeding the
zener voltage (plus the diode forward
voltage drop).
If a transient voltage higher than 33V
appears on the output, as when switching
relays or other inductive loads, the zener
conducts and prevents the output voltage
from exceeding approximately 33V. This
method of protection does not sig¬
nificantly increase the release time of a
relay connected to the output, as would
occur with a diode across the relay coil.
The voltage that the outputs of the
ULN2803 can withstand without protec¬
tion is 50V.
The total current flowing through the
ground pin of IC5 can reach 4A if each
output has 0.5A flowing into it. To
prevent heavy currents from being
directed through the thin ground tracks
on the PCB, the return paths for the digi¬
tal loads must be connected to the 0V ter¬
minals of the digital output socket SK4,
which can then be connected externally
to the (-) supply terminal of the interface
power supply.
In the event that the ground connection
to SK4 becomes disconnected, resistor
R54 (100 ohms) prevents damage to the
board by isolating the main circuit
ground from the digital output ground.
The input currents to IC5 also flow
through this resistor, but it is small
enough not to effect normal operation.
A to D converter
The analog to digital conversion is
done entirely by IC4, a TLC542. This
device has 11 analog inputs, which are
selected one at a time by a 4-bit serial ad¬
dress entered via pin 17. The analog input
voltage is converted to an eight-bit num¬
ber which is then available as serial data
from pin 16.
One clock input simul¬
taneously causes the address to
be read in and the data to
be generated ready for output.
The TLC542 has an internal
clock which controls the con¬
version process. The EOC (end
of conversion) output
generates a low to high transi¬
tion at pin 19 whenever a con¬
version is completed.
To convert the analog input
voltages to digital values, an
external reference voltage is re¬
quired. The reference voltage
inputs are Vref(+) at pin 14 and
Vref(-) at pin 13, which in this
circuit are connected to Vcc
and GND respectively. The
relation between the digital out¬
put value (N), the reference
voltages V- and V+ and the
analog input voltage Vin is given by the
following formula:
N = integer value of
[255* (Vin - V-)/(V+ - V-)]
= integer value of [51.0*Vin]
when V+ = +5V and V- = 0V
The accuracy of the conversion
depends on the actual value of Vcc,
which can be anywhere between 4.8V
and 5.2V with the nominal 5V regulator
used for IC7 (a 78L05). This is a scale
error that can be easily removed by the
computer program, to get an accuracy
typically as good as one LSB (20mV)
over the range 0 to +5V.
The analog inputs to the TLC542 are
protected by internal clamping against
voltages that go outside the range 0 to
+5V. These clamps can withstand cur¬
rents of up to +/-20mA individually, or a
total input current for the whole IC of +/-
30mA. The external lk resistors in series
with the inputs allows the terminal volt¬
age to reach approximately +25V or -
20V before damage occurs.
The interface has 10 inputs for external
connections and two dedicated inputs.
The eleventh input of IC4, pin 12, is con¬
nected via divider network R65/R66 to
Vb, the input to the 5V regulator. The
voltage divider is arranged so that when
Interface specification
Analog outputs (2):
Voltage range
0 - 5V unloaded
Resolution
8 bits (20mV/step)
Source current
20mA approx.
Sink current
5uA for 20mV (1 LSB) error at 0V out
Digital outputs (8):
Output sink current
500mA maximum (open collector)
Output voltage
33V maximum
Output protection
33V clamp, all outputs to ground
Analog inputs (10):
Voltage range
0-5V
Input resistance
typically >100M
Resolution
8 bits (20mV/step)
Input protection
+/-20mA abs. max input current
+/-30mA abs. max total input current
Computer port requirements:
Centronics type parallel printer port; interface has a 25-pin
female ‘D’ connector, with standard wiring. CMOS or TTL
compatible
Power supply:
Voltage range
+7.5V to +25V DC
Current drain
typically 8-10mA at 9V DC
ELECTRONICS Australia, June 1995
57
‘DISCOVERY’ SERIES PARALLEL PORT INTERFACE
Vb is 25.5 V, the voltage at the junction of
R65 and R66 is 5V, giving a digital read¬
ing of 255. The regulator IC7 requires an
input of at least 7V to function properly,
so if the digital value read for this input
falls below 70, the program can be ar¬
ranged to give a low voltage warning.
The twelfth input of IC4 is an internal
connection to the mid-point between the
analog reference voltages, and should al¬
ways give a digital reading of 128 +/-2,
irrespective of the reference voltages.
Reading this input is thus an easy way to
test a program.
The power supply
The interface can be operated from any
filtered, reasonably stable DC supply
with a voltage range between 7.5V and
25V. The supply is connected via series
diode D2, which protects the circuit in
the event that the supply polarity is
reversed. It then passes through transistor
switch Q2, which is controlled from the
computer via transistor Q1 if J6 is linked
between pins 1 and 2. Alternatively if J6
is linked between pins 2 and 3, the inter¬
face is switched permanently ‘on’.
The output (collector) of Q2 is fed to
IC7, a 78L05 voltage regulator, as well as
to the supply pin of IC6. Capacitors C14
and C15 provide some filtering to op¬
timise the stability of the 78L05. Diode
D1 prevents the output of the 78L05 from
becoming more positive than its input
under fault conditions, and zener diode
ZD2 prevents the +5V rail from being
driven to a high voltage in the event that
excess voltages are applied to other cir¬
cuit terminals.
If an unregulated power supply is used,
then for best conversion accuracy it is ad¬
visable to use a separate power supply for
relays or heavy loads that are being con¬
trolled by the interface. For example, the
interface can be operated from a 9V bat¬
tery, and relays, solenoids etc., from a
plugpack or 12V battery.
Construction
Assembly of the interface is fairly
simple, with all of the components being
mounted on a single printed circuit board
(PCB) measuring 145 x 68mm. The
DB25 connector SK6 which mates with
the cable from the computer printer port
is fitted at one end.
To place the various components, use
as a guide the overlay diagram which
shows how the components and wire
links (jumpers Jl-6) actually fit on the
PCB. Read the label of the component,
e.g. Cl, from the overlay and then look
up the description next to that label in the
parts list. For example, Cl is an MKT
type capacitor and it has the value 0.1 uF
(100nF); the actual part be marked either
‘lOOn’or‘0.1’.
Some of the components used are ac¬
tually a substitute for a wire link. They
have the appearance of a 0.25W 5% carb¬
on resistor, but have a nominal 0 ohm
resistance, and on the overlay they are
shown as a resistor with the label R0.
These are used in place of permanent
wire links, because they are easier to in¬
stall than wire links and make the board
look more tidy.
Begin construction by mounting the
links and resistors R0-70. To find the
resistor you want, a table has been
provided which shows the colour code
for each value.
The last band of the colour code gives
the tolerance value and is the one that is
farthest from the others. Resistors can be
mounted in either direction, but it is good
practice to mount them with their colour
codes all in the same direction, for ease
of reading the values.
Next mount the diodes D1 and D2
and ZD 1/2. These must be mounted in
the correct direction only, with the
stripe on the very end of the diode cor¬
responding to the striped end on the
overlay diagram.
Now mount the capacitors Cl-15. One
thing to note when identifying a capacitor
is that the value can be marked on it in
different ways; for example ‘103’, ‘10n’
and ‘.01’ are all the same value and are
shortened notations of lOOOOpF, lOnF
and 0.0 luF respectively.
Capacitors Cl-14 are non-polarised
types which can be mounted in either
direction, but C15 is a polarised
electrolytic which will have a negative
(-) or (+) sign marked on it and must
be mounted in the direction shown on
the overlay.
Next mount the integrated circuits IC1-
6. Note that IC’s 1-4 are CMOS types,
which are sensitive to static electricity. To
prevent them from being damaged, note
the following precautions:
• Do not remove them from their
protective foam until you are ready to
install them.
• Avoid touching the pins with your
fingers.
Here is the PCB overlay diagram , showing the location and orientation of all parts used in the interface.
58 ELECTRONICS Australia, June 1995
• Make sure that your soldering iron is
properly earthed.
• Solder the power and earth pins of
each IC to the board first.
Note that the IC’s have a notch at one
end, which goes at the end indicated on
the overlay diagram.
Next mount the transistors Ql-4.
Position them so that in each case the
flat side is facing in the direction shown
on the overlay. Do not press them down
hard onto the board, as this spreads the
leads and can damage the transistor’s in¬
ternal connections.
Now mount sockets SKI-6. The pins in
the pin header type sockets SKI-5 can be
pushed through their plastic casing if too
much force is used on them, so before
you solder them make sure that the pins
are all level.
With the assembly of the board com¬
plete, carefully check all the soldering.
Look especially for dry solder joints, and
solder bridges which may be shorting
tracks together.
Programming control
Finally, a bit more detail on the way
the interface can be controlled from your
PC program.
The data input to the shift registers
which drive the DAC and digital outputs
is pin 14 of IC1, which is fed from pin 2
of the printer port (SK6). Looking at
Table 1, pin 2 is controlled by bit 0 of the
8-bit byte fed to the port’s base address.
So we have to send our data to the LSB
of the base address, one bit at a time, and
follow each bit with a clock pulse at bit 1
of the same address (SK6 pin 3).
For example, to set the voltage at
analog output 1 (the second DAC, at
SK2) to IV, the following sequence has
to be followed:
1. Convert the voltage to the equivalent
digital value of (Vout/20mV) =51
(rounded to nearest integer value).
2. Work out the equivalent 8-bit binary
value to be sent to the printer port; here
it is 00110011.
3. Send the MSB of this binary value
(here 0) to the port base address, by as¬
sembling the following data byte and
writing it to the port I/O address:
bit 0 = 0 (value MSB)
bit 1 (clock input) = 0
bit 2-6 = 0
bit 7 (power on/off)
= 1 (to turn the power on)
4. Send the same byte as in (3)
again, but this time with the
clock bit (bit 1) set to 1.
5. Finally send the same byte
yet again, but with the clock
bit set back to 0, to finish the
clock pulse.
PARTS LIST
Resistors
(All 1/4W, 1% unless otherwise stated)
R1 1M
R2-11,55-64 Ik
R12-19 10k
R20-28,37-45,66,70
30k
R29-36,46-53 15k
R54 100 ohms
R65 7.3k
R67-69 100k
R0 (0 ohm carbon film
1/4W 5% construction)
Capacitors
C1,14 O.luF (lOOnF) MKT
C2-11 220pF ceramic
Cl 2,13 1nF(1000pF, 0.001 uF) MKT
Cl 5 10uF 25VW RB electrolytic
Semiconductors
D1,2 1N4148 small signal diode
ZD1 1N4752 33V/1W zener
ZD2 1N4735 6.2V/1W zener
Q1 BC549 NPN small signal transistor]
Q2 BC559 PNP small signal transistor
IC1 -3 74HC595 shift register
IC4 TLC542I serial ADC
IC5 ULN2803 octal Darlington driver
IC6 LM358N dual op-amp
IC7 78L05Z 5V regulator
Miscellaneous
SKI-3 Two-way SIL pin header and plug
SK4,5 12 way SIL pin header and plug
SK6 25 pin, PCB mount ‘D’ socket
PCB 147 x 71mm, coded ZA-1205;
216-type 9V battery snap; two 9mm
long M3 bolts with washers and nuts.
6. Repeat steps 3-5 for all the remaining
bits of the binary data byte worked out
in step 2.
7. Since the above steps will have only
sent out the data byte to IC1, another
eight clock pulses are required in order
to send it to IC2, for the second DAC.
Do this by repeating steps 3-5 again,
but with either a dummy data byte (all
zeroes), or else with the data for DAC1.
8. Finally, load the latch of IC2 by
sending the following byte to the base
address:
bits 0-2 = 0
bit 3 (load IC2 latch) = 1
bits 4-6 = 0
bit 7 = 1
9. Send the same byte as in (8) again,
but with the latch load bit (bit 3) set
to 0.
Resistor Colour Codes
Value
4 Band 1%
5 Band 1%
100
Brn Blk Brn
Brn Brn Blk Blk Blk Brn
Ik
Brn Blk Red
Brn Brn Blk Blk Brn Brn
7.3k
Vio Org Red
Brn Vio Org Blk Brn Brn
10k
Brn
Blk Org Brn Brn Blk
15k
Brn
Grn Org Brn Brn Grn
30k
Org Blk Org
Brn Org Blk Blk Red Brn
100k
Brn Blk Yel
Brn Brn Blk Blk Org Brn
1M
Brn Blk Grn Brn
Brn Blk Blk Yel Brn
10. Finally, enable the IC2 output gate
by sending the following byte to (base
address + 2):
bit 0 (IC1 output enable) = 0 (or 1 if
DAC1 is to be enabled as well)
bit 1 (IC2 output enable) = 1
bit 2 (not used) = 0
bit 3 (IC3 output enable) = 0 (or 1 if
digital outputs are to be enabled as
well)
bit 4-7 (not used) = 0
The output of DAC2 should now be
IV, available at SK2.
The equivalent programming for
analog to digital conversion will not be
described, but the following information
should allow you to work out the re¬
quired steps yourself. As shown in Table
1, the control inputs to IC4 are via the
printer port’s base address, and its outputs
are via (base address + 2).
The normal control sequence
needed for analog to digital conversion
is as follows:
1. Chip select (CS) of IC4 starts high,
and is then brought low to enable the
device. The MSB of the last conversion
automatically appears on the output.
2. On the first four rising edges of the
I/O clock (pin 18), the input address is
shifted into IC4, with the MSB first.
The negative edges of these clock pul¬
ses shift out the second, third, fourth
and fifth most significant bits from the
last conversion. Sampling of the analog
input begins on the fourth falling edge
of the I/O clock.
3. Three more I/O clock pulses are ap¬
plied and the sixth, seventh and eighth
bits of the last conversion are shifted
out on the falling edges of these pulses.
4. The eighth and final I/O clock pulse
is applied. On the falling edge of this
pulse, the EOC output goes low and the
sampling and conversion continue, for
about 32us. The I/O clock input must
remain low or the CS (pin 15) taken
high, until the conversion is completed.
The EOC output goes high to signal the
end of the conversion process.
5. Steps 1-4 are repeated to read the
result of the conversion.
Using this sequence as a guide, you
should be able to work out the program¬
ming to achieve it. Remember that the
input selection address for IC4
must be sent to it via pin 8 of SK6,
corresponding to bit 6 of the
printer port base address. As the
serial clock line of IC4 is fed from
pin 3 of SK6, you’ll again need to
follow a similar clocking sequence
as for the output programming,
with a 0-1-0 bit sequence fed to bit
1 of the printer port base address
to produce each clock pulse. ❖
ELECTRONICS Australia, June 1995
59
Construction Project:
CFI & FLUORO
LAMP INVERTER
Fluorescent lamp inverters are not new, but how about one that can drive compact fluoro ‘energy
saver’ lamps? This project can supply a load up to 40W at 350V DC from a 12V battery, is highly ef¬
ficient and connects directly to a compact fluorescent lamp. But there’s even more, as you’ll see...
by PETER PHILLIPS
Battery powered inverters that can
drive a fluorescent lamp have featured
before in EA y and these projects have al¬
ways proved popular. However, we have
never described one that can directly
drive a compact fluorescent lamp (CFL),
or ‘energy saver’ lamp as they are also
called. These lamps have been available
now for about five years, and were
described at length by Jim Rowe in the
September 1991 edition, in Forum. Fur¬
ther discussion on these lamps can also
be found in Forum, November 1992.
The main features of a CFL compared
to an incandescent lamp are five times the
efficiency, and eight times the lifespan.
This means a 15W CFL has the
equivalent light output of a 75W
incandescent lamp, and it lasts
eight times longer. As well, a
CFL has a better ‘light colour’
than a conventional fluoro,
making them more suitable for
domestic use.
Anyone who relies on battery
power is always interested in
electrical efficiency. For these
people, the CFL has probably
been seen as a desirable, if un¬
reachable solution to an efficient
12V DC lighting system. In fact,
those who have tried to power a
CFL from a DC to 240V 50Hz
inverter have often found the life
of the CFL reduced to a mere
few hours. This is particularly
true if the inverter output is a
square wave, as is often the case.
The answer is to drive the
lamps from a DC supply, not AC.
Of course that’s not all there is to
it, and we’ll have more to say
about the CFL later, but first a
closer look at other aspects of
this project.
The project
This project comes from Oatley
Electronics, with much of the
design done by Conrad Marder. The in¬
verter is based on a switching IC, type
SG3525, and has MOSFETs as the
switching devices. A specially designed
transformer and high speed diodes com¬
plete the main component lineup.
The inverter is extremely efficient,
and virtually no heat is generated in
the circuit when it’s driving a 20W
load. This means virtually all the input
power is fed to the tube and converted
to light output.
The normal output voltage of the in¬
verter is around 350V DC and several
CFLs can be connected to the one in¬
verter, up to a total load of 40W or so.
Each lamp can be switched on or off as
required, so you could have a conven¬
tional lighting system based on CFLs
running from the one inverter. We’ll
have more to say about this aspect later,
but as we said in the introduction,
there’s more...
Any fluorescent lamp is more efficient
than an incandescent lamp, and battery
powered fluorescent lamps have been
marketed for years. However as many
people will be aware, the lifespan of the
tube in these units is often quite short.
The main reason is that the tube is not
being driven correctly, because the tube
filaments remain cold during
operation. The inverter we’re
describing here cannot directly
drive a fluorescent tube, as it
has no inherent current limiting.
A conventional ballast can’t
be used, as the output of the in¬
verter is DC. However Oatley
Electronics has been able to
obtain two types of electronic
ballasts that can be used with
this inverter.
The first, shown in Fig.l, suits
an 18 to 20W tube. The output of
the inverter is connected to the
input of the electronic ballast,
which as shown in the photo,
connects to the tube.
The second, shown in Fig.2 is
a more elaborate electronic bal¬
last that features a dimming con¬
trol. This unit is for 32 to 36W
tubes, and an external DC volt¬
age or a 100k ohm variable resis¬
tor can be connected to the unit
to vary the brightness of the tube.
As before, this ballast connects to
the output of the inverter.
60
ELECTRONICS Australia, June 1995
This project lets you operate a compact fluorescent lamp from a 12V battery.
The overall high efficiency makes it ideal for boaties, campers and anyone
relying on battery power.
The important point is that in both
cases the tube is being operated in
the correct way. That is, the fila¬
ments remain hot during operation
and are used to start the tube. This
means the life of the tube is not
compromised by the usual cold start
and cold operation provided by many
portable fluorescent lamps.
Electronic ballast
In an electronic ballast, the incoming
240V mains is applied directly to a
mains-rated rectifier, usually comprising
four 600V 1A diodes. The resulting DC
from the rectifier is filtered with a 10 to
20uF 400V electrolytic capacitor, and is
then applied to an inverter.
For this reason, an electronic bal¬
last can operate from a 350V DC
supply, of either polarity. In this
case, two of the diodes in the bridge
conduct continuously. In fact, the
complete rectifier could be
removed, but this is usually imprac¬
tical and polarises the inputs.
Apart from giving a flicker free start,
an electronic ballast offers a number of
advantages over the conventional iron-
cored ballast.
Perhaps the most important is the
elimination of the strobing effect, due
to the relatively high operating frequen¬
cy of the inverter in the ballast.
Fluorescent tubes operating at 50Hz are
often traced as the reason for headaches
and the like, so increasing the operating
frequency solves these problems.
As well, there’s no buzzing caused by
loose laminations, the fluorescent tube
has a longer life and the overall efficien¬
cy of the light is increased. So even if
you are not interested in using the in¬
verter with a CFL, there’s plenty of
reasons to use it with an electronic ballast
and a conventional tube.
The prices of each system are given at
the end of the article, including a price
for the inverter kit with a CFL. In fact,
before describing the inverter, we need to
explain a few things about CFLs.
About CFLs
It would be nice to be able to say that
this inverter will work with all CFLs.
However, this is not the case, as it ap¬
pears there are at least three different
types on the market.
While there’s no reason to, most people
assume that a CFL has an electronic cir¬
cuit to achieve the high efficiency. In
fact, the tube design is mainly responsible
Fig. 1 (above): This shot shows the 20W electronic ballast
described in the article. The ballast connects directly to the
output of the inverter and is shown here connected to an
18W 600mm fluorescent tube.
Fig.2 (right): The electronic ballast shown here is suitable
for 32 to 36W tubes, and features a dimming control. It
connects to the output of the inverter and gives flicker free
start-up.
ELECTRONICS Australia, June 1995
61
LAMP INVERTER
for the efficiency, and the electronics is
simply an electronic ballast as already
described. For instance, one type of CFL
has an internal iron cored ballast and a
starter integrated with the tube. That is,
it’s much the same as a conventional
fluorescent light fitting. This type of CFL
is quite heavy, and one version is the
Philips SL series, where the actual tube is
housed in a translucent dome. So, be¬
cause it uses a conventional ballast, it
cannot be operated from a DC supply as
produced by our inverter.
The next type is all electronic, and at
first glance seems identical to the
electronic version that will work with
this inverter. However, this type re¬
quires a 50Hz supply, and operates
rather inefficiently when connected to a
DC source. The block diagrams in Fig.3
show the difference between the two
types. In (a), the incoming 240V AC is
applied to a bridge rectifier with a filter
capacitor of at least 10 to 20uF. The
resulting DC supplies the inverter that
drives the fluorescent tube. This type of
CFL will work with the inverter
described in this article.
The version that doesn't work with this
inverter is shown in Fig.3(b). As before,
the incoming mains supply connects to a
bridge rectifier, but now the filter
capacitor is less than a microfarad. A fifth
diode (D1 in Fig.3) isolates the real filter
capacitor from the bridge. With this cir¬
cuit, mains current flows virtually all
the time, unlike the previous circuit,
where mains current flows for short in¬
tervals at the peak of each cycle. Also,
the inverter operates from a DC-plus-
100Hz unfiltered rectified AC supply.
The important point is that CFLs fitted
with this circuit are not suitable for use
with our inverter. While the tube will
light, the current taken from the battery is
nearly twice that when the correct type of
CFL is used.
Fig.3: The basic
internal circuit of a
CFL that will work with
the inverter is shown
in (a). The version that
will not is in (b). Notice
in (b) that the IOuF
filter capacitor is
isolated from the
mains by D1.
As far as we can make out, this
type of circuit is used in those
CFLs that come packaged as a base
and separate plug-in tube. They are
often cheaper than the type that will
work with this inverter, and we’ve
seen at least two brands.
The easiest way to tell if the correct
type of CFL is being used is to measure
the DC current taken from the 12V supp¬
ly. If the power input to the inverter is
about equal to the rated power output of
the CFL, then all is well. If not, the
wrong type of CFL is being used...
The circuit
The circuit of the inverter is shown in
Fig.4. The main component is IC1, type
SG3525. This IC is designed for use in
switch-mode power supplies, and fea¬
tures totem pole output drivers that can
quickly charge and discharge the input
capacitance of the MOSFETs. This im¬
proves the efficiency of the inverter, as
the turn-on and turn-off times of the
MOSFETs are kept extremely short.
The oscillator timing components are
C2 and Rl, with a charge time of 12us
and a discharge time of lus, giving an
operating frequency of about 75kHz.
Capacitor C4 provides a ‘soft start’
and is charged by an 50uA constant
current source inside IC1. This causes the
duty cycle of the output signal from pins
11 and 14 of IC1 to slowly rise to 50% as
C4 charges.
A soft start is needed because of the
relatively large filter capacitor in an
electronic ballast or a CFL. Further start¬
up current limiting is provided by R4,
which for best reliability is specified as a
wire-wound 5W resistor.
The inverter section consists of a push-
pull inverter with the two primary wind¬
ings of T1 connected to form a centre tap.
The primary current is switched via
MOSFETs Q1 and Q2. The secondary
voltage is directly proportional to the
turns ratio of the transformer, and is
therefore determined by the DC voltage
supplying the circuit.
The secondary voltage from T1 is con¬
verted to DC by a bridge rectifier com¬
prising four high speed diodes. The usual
output voltage is around 350V DC. The
output voltage is not regulated unless it
exceeds 370V, as regulating the voltage
lowers the efficiency of the inverter and
is not necessary in this application
anyway. The reason is that a CFL or an
electronic ballast can operate over a wide
voltage range, with a relatively constant
light output.
Because of the leakage inductance
Fig.4: The circuit consists
of a double ended inverter
with the two primary
windings of the transformer
connected to form a
centre-tap. The MOSFETs
are driven with a square
wave from IC1. Regulation
of the circuit only occurs
when the output voltage
exceeds 370V DC.
62
ELECTRONICS Australia, June 1995
Fig.5: This photo shows a close up of the inverter PCB. The MOSFETs in this
board are type MPT50N05E and have a different package to the specified P222
devices. See the layout diagram for details.
between the two primary windings of T1,
spikes are generated at the drain ter¬
minals of Q1 and Q2 when these devices
switch off. The spikes are clipped by
ZD1 and ZD2, to prevent damage to the
diodes in the bridge rectifier connected
to the secondary of Tl. Diodes D1 and
D2 prevent the zener diodes conducting
in the forward direction.
Construction
The kit of parts for the inverter in¬
cludes a silk screened PCB that
shows the component layout. As¬
sembly is therefore very straightfor¬
ward. The photo in Fig.5 shows a
close-up of the inverter and Fig.6
shows the layout diagram.
As usual, install the passive com¬
ponents first, taking care with the
polarity of the diodes and the
electrolytic capacitors. An IC socket for
IC1 is optional.
If the inverter will only be used with
20W loads or less, there’s no need to
add a heatsink to the MOSFETs. For
40W loads, you have two options: fit
heatsinks to the P222 MOSFETs, or use
MOSFETs type MPT50N05E. These
latter devices are in a TO-220 style
package which has a metal tab. They
also have a higher current rating than
the P222 devices. While they can
power a 40W load without a heatsink,
for best reliability a small heatsink
should be added.
The P222 devices are in a TO-126 style
package, but without the usual hole
drilled through the package. This means
the heatsink has to be of the clip-on type,
as there’s no way of otherwise attaching
it. As we’ve said, the heatsink is only
needed if you want to use the inverter
with a load greater than 20W.
Testing
Once you’ve built the inverter, con¬
nect a suitable load to the output and
apply 12V DC to the input. It’s im¬
portant to add a fuse between the battery
and the inverter. Otherwise a fault
could cause a large battery current to
flow, causing considerable heat in the
conductors and damage to the circuit. A
5A 3AG fuse in an in-line fuse holder
will suit most applications.
Remember also that the output volt¬
age is a lethal 350V DC. For this reason,
use 240V mains rated wiring from the
output of the inverter.
As a guide to its operation, the
prototype inverter takes about 180mA
from a 12V battery when no load is con¬
nected. When a Philips PL Slimline
Electronic 20W CFL is connected to the
inverter, the battery current is about 1.8A.
As the light warms up, the current drops
slightly. If the load current is exces¬
sive and the no-load current is correct,
suspect the load. (Refer back to the sec-
Continued on page 87
netal tab <or face)
Fig.6: Here's the layout of the PCB. The MOSFETs can be either of two types, but
both are installed with the metal tab or metal face as shown.
i
Short Cow;
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PC SYSTEM HARDWARE
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Duration: 3 days Fee: $560
Courses can be conducted on site
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ELECTRONICS Australia, June 1995
63
READER INFO NO. 17
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TEMPERA
CONTROL
This handy and compact unit can switch 10 amps
at 240V AC under the control of a temperature
sensor - and its budget-priced. The temperature
setting must be calibrated manually, but can be
set from sub-zero temperatures, to around 100
degrees Celsius or more. A PCB jumper allows
the unit to be set to switch the circuits relay either
on or off when the desired temperature
is exceeded.
EA August ‘94
K10580
<Q9^>
10058^
dimmer for
incandescent lamps
Need a dimmer for a large domestic or stage
application?
This unit will dim an incandescent or halogen
lamp load of up to
2400 watts. It can
also dim 12V
transformer-driven
halogen lamps or
be used for fan
speed control.
SC August ‘94
MCAD ZAPPEtt
Do you have a few suspect Nicad batteries
lying around in your kitchen drawer? Why
not try bringing them back to life with this
Nicad Zapper? It zaps the cell with a high-
voltage, high-current burst to blast away any
internal shorts caused by dendrites.
SC August ‘94
A Simple
Go/No-Go Crystal
r'Lsisi b™ This simple Sircuit will he
Chprlrpr This simple Circuit will help
tcL/Vc / you sort through that pile
of crystals lying on your workbench. If the
crystal works, the LED lights. Best of all, it
can use parts which you probably already have
in your junkbox.
SC August 94
Build the
PreChamp - a
tiny, versatile
preamplifier to
mate with the
CHAMP!
This handy and compact unit can switch 10 amps
at 240V AC under the control of a temperature
sensor - and its budget-priced. The temperature
setting must be calibrated manually, but can be
set from sub-zero temperatures, to around 100
degrees Celsius or more. A PCB jumper allows
the unit to be set to switch the circuits relay either
on or off when the desired temperature
is exceeded. EA August 1 94
Build the MiniVOX
voice operated relay
This tiny board is a
voice-operated
switch designed
to fit into the
tightest
space. It
uses a single
IC SC includes a SPDT 12VDC relay. It
has almost no turn-on delay SC a 3-
second release time. >^777.7^
****•»" ($14^95,
A long-wove AM receiver
for aircraft weather
information
This simple receiver uses two ICs & will pick up
airport weather beacons in the LW band. Use it
to receive up-to-the-minute weather reports. It
runs off a 9V battery & is easy to build.
SC Sept. 94
Automatic discharger
for Nicad battery packs
If you own equipment
which uses nicad
batteries, then this
discharger is for you.
Use correctly, it will
maintain the full
capacity of your
battery pack & extend
its useful life. It can
even rejuvenate an
old battery pack that's
suffering from the
memory effect.
SC Sept 94
Do you hate fluorescent lights with their
inevitable flick, flick, flicker at switch-on, the
flicker while they are running & the buzz or hum
of the ballast? Now you can replace the internals
of your fluorescent light fittings with this
electronic ballast. It is highly efficient, gives
instant starting & has no flicker, buzz or hum.
SC Oct '94 /1<I0625'
1.95,
59 -
BUILD THIS TALKING HEAOUfiHT
REMINP |
Ever
leave
y o u r
car’s
headlights
TMKiMO HCAOUOm *
RCMMMOCrt
«COh
MJSL
or parking lights on? Flatten the battery
too? If so, you need this talking headlight
reminder. If you accidentally leave your
headlights on, it tells you to switch them
/^K10630'
SCOct. 94 ($79.95,
BEGINNERS
VARIABLE DUAL¬
RAIL POWER SUPPLY
If you are
just
beginning in
electronics,
then you’ll
properly baulk at building a mains-
operated power supply. This project uses
a plugpack which means that you can make
your own variable dual-rail power supply
without worrying about main s^wiring .
sc oct 94 /^kT0635
Needs plug pack Ml9017. ( J J Q # 9 £
CLIFFORD- A PESKY
LITTLE ELECTRONIC
CRICKET
Meet Clifford - our new little pesky insea
friend. A cousin of Horace the Cricket,
he has a lot to say - provided it’s dark.
He’s easy to look after SC doesn't eat very
much - one 9V battery will do him for a
month! SC Dec 1 94
Hnoft\A ou/wios txt tnto rnj( i '< n i m./ uiutnri \oiii /
rfc
ri<
ri<
rk
Ik
rk
rk
rk
We ore commited to delivering the latest in computer products & accessories!
SECURITY KIT
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SYSTEMS; ~ SBiSl
Safely secure your
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Includes • heavy duty TV! ft
coated steel cable*3 |
permanent self adhesive 1
mounting plates *1 padlock ■
and 2 keys.
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80 Watt with • 4" woofer, 2" tweeter
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CAT No. A15206
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woofer 6W amplified
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Dimension: 108W x
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Gross weight: 2.0kg.
AVAILABLE TO ORDER
BY MAIL ORDER
New io wee pstcesn
IEC TO 3 PIN
MAINS CABLE
PI 0252
WAS $9.95 JBHRHnE
A multifunctional tool
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for:
•Soldering (up to 400°C)
•Heat Shrinking
•Repairing
•Cutting
•Torch(upto 1300°C)
Runs on standard butane
gas lighter fuel. Up to 60
minutes continous use. 5
tips included.
IEC EXTENSION
CORD (M-F) i
PI 0254 I
W/ $c?95
SUPA SPECIAL
CONNECTED YOUR Off ICE COMPUTERS AND*m+£Z'*Wf
TRANSfER PILES EASILY- SAVE YOURSELMS’r^C'*
LOTS Of TEDIOUS DISK COPYING. S r \ \\
"LAPLINK" (make 2 computers talk to each other). Stop going through the W || || h 5
tedium of copying to and from floppy disks. Ideal for Laptop to Desktop file ® %Mmk M I
transfer, usergroup meetings, etc. Dos 6.0,6.2. INTERLINK.EXE works like BL VHP JJ . fe «
a basic network with only 1 client and 1 server allowing for shared resources ™ UJ
like printers and hard drives. Use either a serial or parallel (bi-directional) fl^MI
port. Use a Ritronic Laplink cable serial (PI 9070) or parallel (PI 9072). "
Follow the simple instructions in your DOS manual:- P19073
i.e. Edit your config.sys on the client computer by adding the line: 5M PARALLEL DB25 M/M
device=c:\dos\interlink.exe Restart your computer. Crtl+Alt+Del C V JR BA
On the server run the program INTERSEV.EXE ^ |
For more information type help inlerserv at the DOS prompt and read the
on screen txt. p 1 9074
These cables are suitable only for exchanging data between systems & not 10M PARALLEL DB25 M/M
for playing interactive games such as Doom, Rise of the Traid, Wacky £ ■ 4% BA
Wheels, Descent, etc. You will need a serial cable such as the Serial | **
SCANPLUS COLOUR 6000-
24 BIT 16.8 MILLION COLOUR^S^
SCANNER ♦ IBM PC/
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width • High speed (one pass
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This powerful 486DX2-66 system is perfect for I
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Monitor - 1024 x 768mm 0.28mm Dot Pitch • Ritron
Mouse Pad* 101 High quality keyboard* 16-bit Sound
Card • Joystick & Mouse* Multispin CD ROM Drive*
Magnetically Shielded Speaker • Microphone •
Windows 3 11* MS-DOS 6.22
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Configuration:*PCI Slot Motherboard* PCI
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Tower Case and 200W PS* 1.44 3.5" F.D.D.
•Ritron Mouse Paa* 101 High quality
keyboard* Sound Blaster 16 Sound Card*
Joystick & Mouse • Magnetically Shielded
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•MS DOS 6.22* Windows 3.11
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(FIRST 2 YEAR ON-SITE ) MELB MET AREA
•Brilliant colour . 24 bit true colour images for your
i TT Window-based DTP & presentation packages* High
(XOrFaae-11 resolution - up to 1200 dpi*Po"«H ul image software -
— * * atbed PhotoFinish 3 0 software tor image editing. * TWAIN
compliant -scan easily within any compatible
* applications. Simply select the acquire scanner command.
OPTIONAL: •Power OCR . optional Recognita Plus OCR
J: Auto-Document Feeder (ADF-I) and transparency unit (TMA-
^H). INCLUDES: INTERFACE CARD. PHOTOFINISH 3 . 0 . MEDIAMATE
SENT AVON SOFTWARE, TWAIN DRIVER. USERS MANUAL
Scanmate 256
>gr<.
an affordable price. Scans up to
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Card,Photofinish 3.0, Media Mate presentation
software. SmartPage Direct OCR software.
TWAIN compliant software. Users Manual, etc.
I4I4VQE High speed desktop
fax modem V.32bis (14.4 kps) data
& fax modem. $199
l4/4VQH'ri\gh speed IBM can
fax modem V.32bis (14.4 kps) data
& fax modem. $229
Bundled with WinFax Lite
Easy painter .$179
Digitiser pad for freehand drawing
HiMouse Cordless .. $79
Control cursor up to 2 meter
Laser Pointer ........ $79
Highlig ht what you want in your
T^PTTYTTTTITTT^ 1
LX300 264 Cps Draft, 9 pin dot matrix .$249
With colour option . $349
LQIOO 200 Cps Draft, 24 pin dot matrix .$289
LQ150 216 Cps Draft, 24 pin dot matrix .$339
With colour option . $389
Stylus 400 48-nozzle inkjet, 180Cps,360dpi .. $389
Stylus 800+ 48-nozzle inkjet, 255Cpi,360dpi $459
Stylus Colour 200Cpi,3601720dpi full colour SD3HJ
EPL 3000 300dpi, 4ppm, laser printer .$849
EPL 5200 300dpi, 6ppm, laser printer .$1149
EPL 5600600dpi finnm laser orinter. RISC. $1599
Scanmate Co
Economical 24-bit
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Scanmate 1600DPI Colour
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RITRON COMPUTER SYSTEMS DISCOUNTED SOFTWARE I
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4860X2-00,.SI 639 MS Office Pro *5775
406DX4- l $ 1 796 MS orticc Pr0 Dc,uxc 4 * $869
Pentium - 1845 ggSn'H™ .W** S 9 9
Pentium ’“66* ...mM>.T59/ $ 1 895 MS Dangerous Creatures. '$60
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Pentium’" 90* .*$1979 $2379 .... . rr% DA '
PCnt, TJr'£ 0 ’ 52390 52891 ^an^usSres” 4 S 55 ?
•External 2S6H Cache _.mc £ n „ * M c W ork< A * '4
66* 9v $ 1895 MS Dangerous Creatures. * S 6 0
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All systems include: 4 MEG RAM *420 MEG H.D.D - *MS Money-
CHEAT VALUE!!- 1.44 MEG 3.5 FDD • Mini or Baby AT I 79 1vl ff^.
casing • 2 SPG Ports -101 Keyboard • 3I Slots; VESA puSZZZ^ZTZsic^
Local Bus Motherboard • 14 SUPER VGA (1024X7681
(0.28' DOT PITCH) Colour Monitor -VLB 1MB VGA FREE 3 HOUR m
Cards are supplied in 486 machines AT NO EXTRA for C au*coJiputer
COST (Up to 1 280 x 1 024) Pentium systems now come systems including Mm
with PC! Cards and should be bough! with 8MB of NAM mul timedia systems
11 ifrl :?■! >1 l.’W.’TB J J :< IJ! I d ;?■! K it] iW-V+l 14 y H
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NEW!! COMPUTER CASES
MINI TOWER CASE ..$69
MIDI TOWER CASE ..$89
FULL TOWER CASE $119
All cases come with 200watl
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SUPA MOTHERBOARD UPGRADES
386SX-40* LM 47 $149
366DX-40* 128K Internal Cache LM58 . $229
486DX2-66#256K Cache L B $349
486DX2-80* 256K Cache L B NEW! .$449
486DX4-100* 256K Cache L B L_J^|$499
PENTIUM ■ 60MH^256 C VESA/PCI g^^$649
PENTIUM * 66MHX/256 C VESA/PCI WmBLti $726
PENTIUM- 75MHz®/256C VESA/PCI NEW! $999
PENTIUM *" 90MHr* PCI/VESA $1299
PENTIUM " 100MHz 4 * PCI/VESA $1995
ID CPU. #CYRM CPU Without Asterisk- INTEL CPU
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HciohsJsoitMK^oryt>mee) .... US
WEARNES COD-120 DUAL SPEED CO ROM IDE DRIVE
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562B CD ROM DRIVE DOUBLE SPEED
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HEAD OFFIC E: 56 Renver Rd Gay ton, Victoria, 3168 Ph: (03) 543 7877
MELBOURNE: 48 A’Beckett St. City. Ph:(03) 663 6151. Computers (03) 639 1640
- ■ “ ■ Ph: (03) 874 8888. Fax:(03)
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Fax:(t)3) 874 2288
Fax:(03) 562 8940
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City store open till 8pm on Fridays. Box Hill store open till 3pm on Saturdays. Eg
Tax Exempt sales: RITRON1CS WHOLESALE Ph.(03) 543 2166 Fax.(03)543 2648 ^
RIE BULLETIN BOARD Ph: (03) 562 7877 For SpeciaLs, info & Shareware ^
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Mail Order Hotline 1-800 33 5757
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30 PIN SIMM
1M x 9-70 With Parity $69
4M x 8-70 No Parity $249
4M x 9-70 With Parity $259
72 Pin SIMM FOR PENTIUM m
4M X 8-70 No Parity $269
4M X 9-70 With Parity $289
8M X 9-70 With Parity $529
16MX 8-70 No Parity $899
16M X 9-70 With Paritv $999
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Video Blaster SEIOO. toBffiB $499
Game Blaster CD16 Pk 7 CD Titles $799
TV CODER.$279
16 bit Discovery Pack CD16 2 LEFT ONLY $489
BbitJDiscovery Pack CD8 .$299
NEW Q uaL( j 'speed CD-ROM D rive $649
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• 14* Interlaced 1024x768 (0.28mm Dot pfch) $389
• 14* Non-interlaced 1024x768 (0 28mm Do pth) $429
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• 15” XGA Digital MPRIli 280 x 1 024
* #17” XGA Digtal MPRII 1280x1024
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144M EXTERNAL 14400BAUD
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28.8 FAXMODEM INT 28.800BPS
FM MEANS FAXMODEM
$179
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PRICES ARE PER All disks come with Write
BOX OF TER DISKS **
DESCRIPTION 1-9 10+ 50+ 100+ 500+
5 V < DS/DD $4.50 $4.50 $4.50 $4.30 $3.95
5’ <DS/HD $7.95 $7.75 $7.50 $6.90 $6.90
3 v 2 DS/DD $5.95 $5.75 $5.50 $5.25 $5.00
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■ W W Pentium ~. OverDrive - A Intel486 ™ are registered trademarks ot the Intel Corporation _tAJUiNSO m wm J iUl A 1 leLAB W*
Construction Project:
SINGLE CHIP
CHESS COMPUTER
Keen on chess? How would you like to build your own low-cost chess computer, so you can pit your
skills against it? Here’s a design based on a single microcomputer chip, with firmware developed by
the author. It uses surface mount technology, and is so compact you can either fit it into a matchbox
or build it into a conventional chessboard...
by IAN MITCHELL
‘Chess is the intellectual game par
excellence ’, wrote Newell, Shaw and
Simon in their paper published in the
IBM Journal of Research and Develop¬
ment in 1958, which traced the develop¬
ment of digital computer programs that
play chess. They believed that the ef¬
forts to program chess provided an in¬
dication of the then-current progress in
understanding and constructing complex
and intelligent mechanisms.
I think this probably holds true today,
as just recently a computer called
DEEP THOUGHT has won a chess
game against a Grand Master chess
player. However, it took one of the
fastest parallel computers in the world
and many man-years of programming
effort to do it.
Chess programs have probably been
written for all types of digital computers
ever constructed in the last 40 years,
from four-bit microcomputers to Crays
and all types in between.
Presented here is a chess computer
based on the 68HC705C8FN
microcontroller from Motorola. The
‘FN’ refers to the type of package the
micro controller comes in, which in this
case is a plastic-leaded chip carrier or
PLCC. It’s a surface mounted com¬
ponent and allows the project to fit into
a match box! It is not necessary to con¬
struct the project this way, but it will
certainly be a novelty if you do.
Of course if you decide to construct
the project to fit into a match box (or
something similar) then a normal chess
board must be used in conjunction with
it in order to play against it. Alternative¬
ly you could build it into your own
chess board and thus have a fully self
contained chess computer, like most of
those available commercially. I plan to
build one with a glass top and legs, so
that it can double as a small coffee table.
I have called it the Single Chip Chess
Computer, or ‘SC3’.
The circuit
The SC3 consists of three switches for
entering moves, and four banks of LEDs
for displaying moves and status infor¬
mation. There is no on/off switch, since
the microcontroller is placed into its low
power or STOP mode whenever a
switch has not been pressed for about
eight minutes ago. During STOP mode,
the on-chip clock is stopped and power
is only required to keep the static RAM
from losing its contents — which re¬
quires about lOmW.
Only one of the LEDs from each bank
will be used at any one time, so only
one current limiting resistor is needed
per bank of LEDs. The separate banks
are multiplexed to give the illusion of
more than one LED being on. Debounc¬
ing of the switches is handled by
software, and is incorporated in the
same routine as the LED multiplexing.
The multiplexing routine is called
with parameters to indicate which
LEDs to multiplex.
During multiplexing, the port to
which the switches are connected is ex¬
amined, and if a switch was already
closed the routine waits until the switch
becomes open. At which point a delay
of several loop times is used to
debounce the switch opening, and the
routine then loops waiting for a switch
closure. When a switch being closed is
sensed, another delay for debouncing is
initiated after which the routine returns
with the identity of the switch which
was pressed. A delay in the multiplexing
loop determines the rate of display mul¬
tiplexing, which is about 7ms.
Switch SW3 is also connected to the
interrupt request (IRQ) pin, which
enables the microcontroller to wake up
from its low power mode. Also, if you
Mi
i
OftjDg
The author ’s prototype chess computer PCB is shown here in the centre, slightly
smaller than actual size, with its matchbox case’ on the left and a 50 cent coin
on the right to give an indication of their size.
ELECTRONICS Australia, June 1995
68
about 0.7 volts and also protects the cir¬
cuit from inadvertent reverse connecting
of the batteries.
get tired of waiting for the computer to
make its next move, you can press this
switch to interrupt the routine which is
calculating the next move, and force the
computer to use the best move it has
found so far.
A 4.1943MHz crystal is used in
the clock circuit because they are
readily available and the maximum
device is 4.2MHz. This is divided inter¬
nally by two, giving a bus clock of
2.097MHz. Capacitors C3 and C4 and
resistor R4 are used to ensure reliable
starting of the oscillator.
All unused inputs are tied low, so as
to prevent increased power consumption
should these inputs otherwise stray up
and down. Diode D1 is used to reduce
the peak voltage of fresh batteries by
The firmware
The main building blocks of a chess
computer are the CPU, RAM, ROM, a
timer and an appropriate input/output
mechanism. Apart from the lack of
processing power in the CPU a typical
microcontroller makes an ideal chess
computer. Depending on the algorithm
used to decide the next move for the
computer, it has been shown clearly that
a computer’s chess rating increases in
proportion to its processing power for
a predetermined period of time per
move. While we can’t expect a chess
computer based on a microcontroller
to play at the level of Grand Master, a
reasonable level of play can be ex¬
pected while a bad move is not neces¬
sarily a bug in the program. It is also
clear that as more time is devoted to the
calculation of a move, the better that
move is likely to be.
The firmware for the SC3 consists
of approximately 6000 lines of as¬
sembly code, so a detailed explanation
of its function cannot be undertaken
here unfortunately.
SINGLE CHIP CHESS COMPUTER
Here are the patterns for the top and bottom layers of the chess computer PCB, for those who like to etch their own boards
Note however, that because this board is very small we ’ve reproduced them at 150% of actual size for clarity.
The program was originally written in
C, in order to test and debug the algo¬
rithms, and then translated into 6805 as¬
sembly language. Even so, using this
method still required about two years of
part-time programming to complete.
Why is the program so long? The
answer, in a word, is speed.
Due to the nature of the algo¬
rithm (described below) for
generating and searching
moves in order to find a good
one, it is very important to
make it execute as quickly as
possible. The most time con¬
suming part of the algorithm
is the move generation. Be¬
cause determining the next move is cer¬
tainly the ‘most visited’ part of the pro¬
gram, it must execute reasonably
quickly and efficiently.
The chess board is represented by 64
memory locations, with the pieces for
the computer represented by positive in¬
tegers and the pieces for the opponent
represented by negative integers. A
vacant square is represented by a zero.
With this in mind, the generation of
the moves for the black and white
pieces has been separated, as has the
generation of capture moves as opposed
to non-capture moves (also explained
below), and where possible loops have
been unrolled and code placed in-line. A
sample piece of code for generating a
rook’s move is shown in listing 1.
NCRDIRO is where program flow
Listing 1
NCRDIRO Idx
PTO
index TO position
Idx
DIRN.x
get next board position
bmi
NCRNDIR1
if off the board, next direction
Ida
B,x
see what’s on the board here
beq
NCRNDIR1 ...
RET MOVE
if blank, move ok
comes when checking for non-capture
moves involving rooks. PTO is the last
destination square tried for this rook.
DIRN is a table of board locations for
moving one square north from the cur¬
rent position, with negative values in¬
dicating that a move in that direction
would be off the board. If this is the
case, a branch is performed to a similar
piece of code which tests for moves in a
different direction for this piece. If the
destination square is vacant, then this is
a valid move in as much as it ensures
that the king has not been placed in
check because of this move.
Both the C and the assembly versions
are available on floppy disk, if you are
interested in understanding the code in
more detail.
The SC3 has eight levels of play,
which correspond directly to
the amount of time it spends
calculating the next move.
However if the score as¬
sociated with the latest search
is as good as the score from
the previous search (one half
move less deep), and of
course the move chosen was
the same, then the search is
immediately stopped. The assumption
being that it is highly likely that the best
move has already been discovered to the
best of the program’s ability and that it
is pointless wasting time searching still
further until the time allotted at the level
chosen has elapsed. The SC3 searches
for about 11 seconds times two to the
power of one less than the level of dif¬
ficulty entered, unless the above condi¬
tion becomes true. For example, the
maximum search time on level three is
44 seconds (11 x 2 (3 .
The SC3 uses what is known as a
‘brute force’ method of calculating the
next move. This method appears to be
the method of greatest success, histori¬
cally, in terms of playing human op¬
ponents. Its advantage is that every
single move on the board will be tried
and evaluated and thus the very ob¬
viously bad moves will always be
eliminated. Other methods, which
employ some intelligent scheme of
selecting which moves to consider, were
not as successful because it is extremely
difficult to program such intelligence
into a machine.
The method by which the SC3 uses
to determine its moves is a derivative
of a searching technique called the
minimax algorithm. The minimax al¬
gorithm works by considering, for ex¬
ample, all the moves from the current
board position, and for each of those
moves, all the replies to those moves;
and so on, to a predetermined depth or
level. At which point (a terminal posi¬
tion) a score is calculated based on how
good the position is...
In the SC3 the score is calculated by
considering the material balance only. In
theory it is possible, from the beginning
of the game, to search all the moves
until either a win, draw, or loss has been
found. In practice this is impossible due
to the sheer magnitude of the moves that
would need to be searched. For ex¬
ample, if on average there are about 40
moves available in any given position,
then searching to a depth of only 10
levels (or ply) would require the genera¬
tion of 4010 or 1016 moves!
The minimax algorithm gets its name
from the way it works. That is, the com¬
puter will choose the move leading to
the position at the next level with the
maximum score, knowing that where it
is the opponent’s turn, a score equal to
the minimum score of any of its succes¬
sors is chosen.
The minimax algorithm is a depth-
first search, and by its nature the
memory requirements grow linearly
with the depth of the search — as op¬
posed to breadth-first searching, for
example, where the memory require¬
ments grow exponentially with the
depth of the search. This is an impor¬
tant consideration because of the
limited amount of RAM available on
the 68HC705 for this application.
The actual algorithm used, however,
is a derivative of the minimax algorithm
called the ‘alpha-beta search’ algorithm.
This algorithm is based on the fact that
many paths within the search tree con¬
structed by the minimax algorithm need
not be examined because they will have
99999999
SHIFT
NEXT
OK
SC3
Single Chip
Chess Computer
The artwork for the chess computer’s
front panel, reproduced again at 150%
for clarity.
no effect on the outcome of the search.
The decision whether or not to search a
particular branch of the tree is based
solely on the numeric value of the score
calculated at the terminal nodes. It has
been demonstrated that the alpha-beta
algorithm requires only six times as
long to search the next level in chess,
compared to the minimax algorithm
where it is dependent solely on the num¬
ber of moves at a given position.
Because of the nature of the alpha-
beta search algorithm, the order of
Getting SC3’s firmware
Ian Mitchell, author of this article and
designer of the SC3 Chess Computer,
has generously agreed that Electronics
Australia can supply the chip program¬
ming firmware code as an SI 9 file, to in¬
dividual readers who wish to build the
project and are able to program their
own 68HC705 chips. This file is avail¬
able for downloading on the EA Reader
Information Service BBS, or can alterna¬
tively be obtained by sending us a DOS
formatted 3.5" or 5.25" diskette, plus $5
to cover copying and return postage.
However please note that the complete
source code listings and files are only
available from the author, for a small
fee. The author is also able to program
chips for individual constructors, again
for a small fee.
The author is also retaining commercial
copyright to the SC3 software and
firmware, so that kit suppliers and other
people who may wish to use the
software/firmware in kits or other com¬
mercial products will need to negotiate
directly with the author. All enquiries
should be addressed to Ian Mitchell, PO
Box 937, Sandy Bay Tasmania 7006;
phone (002) 24 1078. __
moves visited will impact heavily on the
number of positions searched, and thus
the duration of the search. Most chess
programs will generate all the moves at
each level and then sort them in order of
value, defined by a comparatively quick
evaluation routine. For example, a
queen captured by a pawn will rate
higher than a pawn captured by a
bishop, and so forth.
Since the 68HC705 has very limited
resources in terms of RAM it is impos¬
sible to generate, store and sort all the
moves at each level, so a compromise is
made. It turns out that it is only neces¬
sary to store enough information to
determine what the next move will be,
each time the move generation routine is
called. Only nine bytes of information is
required at each level to uniquely iden¬
tify the move made in a particular posi¬
tion, and the same information is of
course used to restore the board after the
move has been searched.
Using this method it’s not possible to
directly sort the moves to improved the
search time. However it is possible to
improve the search time by dividing the
move generation into two separate sec¬
tions, the first of which generates all the
capture moves and the second all the
non-capture moves. This sometimes in¬
volves scanning the board twice, but the
savings in search time easily make up
for this. If there is a capture move in any
given board position it is highly likely
that based on the properties of the alpha
beta search algorithm, the second scan
of the board will not be required.
As described before the score
evaluated at the terminal positions of the
tree is based on the material balance.
Whilst this is certainly an important
piece of chess knowledge, it is by no
means the only piece.
The SC3 uses a different scoring
method at the root of the tree when the
alpha-beta search returns more than one
move with the same score. In fact, three
different position evaluation functions
are used to determine the move chosen
at the root for search scores of equal
value: one for the opening, another for
the middle and another for the end
game. These positional evaluation func¬
tions use a combination of centre con¬
trol and mobility — the number of
moves available in the given position.
Playing with SC3
The SC3 uses the common algebraic
form of chess notation to identify the
square from which the piece moves and
the square to which the piece moves.
Board co-ordinates are always refer¬
enced with respect to the human player.
ELECTRONICS Australia, June 1995 71
SINGLE CHIP CHESS COMPUTER
That is, square A1 is always the square
closest to, and to the left of the human
player regardless of which colour they
are playing.
When the SC3 is first powered up the
green LED ‘DRAW/LEVEL’ (LED 3)
will be on and the ‘ V LED (LED 5) will
be flashing. This is the prompt for you
to enter the level at which you would
prefer the computer to play. Pressing
SHIFT (SW1) will cause the ‘2’ LED
(LED 6) to flash, indicating level 2.
Continuing to press SHIFT will cause
the next corresponding LED to flash,
and so on until the ‘1’ LED will be
flashing again.
After deciding on the level you wish
to play, press the ‘OK’ (SW3) button.
The LED indicating which level you
have chosen will stop flashing, but
remain lit — while the ‘FROM/WHITE’
LED (LED1) will start flashing. This is
the prompt for you to indicate which
colour pieces you wish to play. Pressing
the SHIFT button at this point will cause
the ‘TO/BLACK’ LED (LED2) to flash,
indicating that you wish to play the
black pieces. Pressing SHIFT again will
cause the ‘FROM/WHITE’ LED to flash
again, and so on. Having decided which
colour you would like to play, press OK.
If you have decided to play the white
pieces, you can enter your first move
now. The ‘A’ LED (LED 13) will be
flashing and the ‘1’ and
‘FROM/WHITE’ LEDs will be lit. To
enter, for example, a move from E2 to
E4, press the SHIFT button until the
‘E’ LED is flashing then press NEXT
and the E LED will remain lit while
the ‘1’ LED will start to flash. Press
the SHIFT button until the ‘4’ LED is
flashing. You have now entered the from
part of the move.
To enter the to part of the move (E4),
press the NEXT button again, and the
TO/BLACK LED will light, and then
follow the above procedure. If you
make a mistake, use the SHIFT and
NEXT buttons to correct it.
When you are satisfied that you have
correctly entered your move, press OK.
If you have not entered a legal chess
move the ‘FROM/WHITE’ and ‘1’
LEDs will light and the ‘A’ LED will be
flashing, indicating that the move just
entered is not legal and so you must
enter a legal move. If you have entered
a legal move, the computer will now
calculate its. move. During this time the
MATE LED will blink once every two
seconds to indicate that a move is being
calculated.
When the computer has finished cal-
72 ELECTRONICS Australia, June 1995
PARTS LIST
Resistors
All SMT:
R1-3 10k
R4 1M
R5-8 220Q
Capacitors
All SMT:
Cl,2 O.luF
C3,4 22pF
Semiconductors
U1 MC68HC705C8FN, pre¬
programmed with SC3 firmware
D1 BAS 16 SMT diode
LED1-4 3mm green LED
LED5-20 3mm red LED
Miscellaneous
PC board, coded SC3V12; three push¬
button switches; two 4mm nuts and
bolts; one 4.1943MHz crystal; fine
tipped soldering iron; fine gauge solder;
two 3V batteries; matchbox.
culating its move, the from part of the
move is displayed on the A-H and 1-8
LEDs and the ‘FROM/WHITE’ LED
will be lit. Press the NEXT button to
display the to part of the move, and
the ‘TO/BLACK’ LED will light.
Pressing NEXT will alternate between
displaying the from and to parts of the
move. Make the move on the chess
board and then press OK.
You are now prompted to enter your
next move as before. In general, an LED
flashing indicates the group of LEDs to
which the SHIFT button can effect.
If you choose to play the black pieces,
the computer will be playing white and
therefore will calculate and display its
move first, as described above.
The computer may enter its low
power mode while you are determining
your next move. If this happens, all
LEDs will be switched off but the state
of the game remains intact. To resume
where you left off, press the OK button
and this will ‘wake up’ the computer.
If the last move you entered is a win¬
ning move (the computer is in check
mate) then the ‘MATE’ LED will light.
If the last move calculated by the com-
References
Among the many references used by
the author in developing this project
were the following, which can be recom¬
mended for further reading:
How to Beat Your Chess Computer, by
Raymond Keene and David Levy,
Batsford Ltd.
Computer Games, Vol.1, edited by
David Levy. Springer-Verlag, 1988.
How Computers Play Chess, by David
Levy and Monty Newborn. Computer
Science Press, 1991 .
puter is a winning move (you are in
check mate) then the move will be dis¬
played as usual and the MATE LED
will light as well. If at any point
during the game there are no legal
moves but neither king is in check,
then this is a draw and the ‘DRAW’
LED will light. Again, pressing OK
will begin a new game.
Construction
All of the circuitry for SC3 fits on a
PCB measuring only 51 x 32mm, and
coded 95cc6. The board is double sided,
with plated-through holes, and a small
number of surface-mount components
are used. The PCB patterns for the
board are provided, along with the over¬
lay diagrams to assist in assembly.
It’s important to remember that the
first component to be mounted on the
top side of the board must be the
68HC705. I found it easier to solder the
surface mount components on the bot¬
tom of the board first: C1-C2, R1-R5
and the diode, remembering to observe
the correct orientation of the diode. Use
a fine tipped soldering iron, with a tip
size no greater than one millimetre. Do
not attempt any soldering with a larger
tip, as solder bridges will be inevitable.
Now the 68HC705 should be mounted
on the top side of the board. Because of
the ‘J’ shape of the leads, it may be
easiest to pre-tin all of the PCB pads;
then place the 68HC705 on the board,
observing correct orientation, and while
holding firmly, reheat the solder so that
it flows onto the pins.
Inspect for bridges
Having soldered all the surface
mount components, breath a sigh of
relief and do a close inspection to en¬
sure that there are no solder bridges.
Next, since the crystal is mounted flat
on the top side of the board, bend the
leads carefully at 90° to its body,
about 1.5mm from the seal. Then bend
them again at 90°, level with the side of
the body, and cut so that there is just
enough length to be soldered. Ensure
that the top of the crystal case is clean
and pre-tin it with a small amount of
solder. When mounting the crystal,
solder the top of it to the board so as to
ensure mechanical stability.
The LEDs can be mounted next, en¬
suring correct orientation. Push them all
the way down, so that they are flush
with the surface of the PCB. It is pos¬
sible that the edges of some of the LEDs
may need to be filed down a little, to
ensure correct alignment.
Next mount the three pushbutton
switches so that the tops are level with
the tops of the LEDs. Some of the pins
may be difficult to reach with the
soldering iron from the top, assuming
the pins do not go all the way through,
but it is possible to reach them from un¬
derneath. That is, with the soldering iron
between the top of the PCB and the bot¬
tom of the switch.
Check everything again for solder
bridges or misplaced components. If
everything looks OK, the batteries can
be connected. It’s a good idea to place
a small piece of sticky tape over the
pad closest to the large battery pad
negative, to make handling the bat¬
teries a little easier. It’s also a good
idea to put some sticky tape around the
edges of the cells so that they are func¬
tionally a single 6V battery.
Paper clip bracket
A bracket can be formed from a paper
clip or reasonably stiff wire and the bat¬
teries bolted to the bottom of the board,
with the battery negative making con¬
tact with the board and the positive
making connection with the bracket. If
all is well, LED5 (the ‘1’ LED) should
be flashing and LED3 (DRAW/LEVEL)
should be lit. If not, disconnect the bat¬
tery and check everything again.
Check that all the pushbuttons are
functioning correctly and that the ap¬
propriate LEDs light up. At this point
pressing the SHIFT button SW1 should
light LED6 and so on until LED5 is
again flashing. Press the OK button
SW3 and green LED1 (FROM/WHITE)
should be lit.
If you are going to mount the
SC3 in a matchbox, photocopy the
page with the front panel layout, cut it
out and stick it to one side of the
matchbox.
Next, drill holes for the LEDs and
cover the whole box with a piece of
clear ‘Contact’ for protection.
Since there is not enough RAM to
record all the moves of the game being
played, and because there is no way to
take back a move once it has been
entered, it is a good idea to record
who was playing white, the level chosen
for the game and each move as it is
made, on a piece of paper. If you find
yourself playing a crucial game and a
mistake is made, you can always start
again — entering the exact same moves
as before up to the point where the game
was aborted.
If you’re with me this far, congratula¬
tions. You should now be ready to set up
a chess board, and good luck in pitting
your skills against SC3! ❖
(Continued from page 44)
that the errors may have caused. I believe
Mr Ian Hunt VK5QX, of Salisbury East
in South Australia, also placed extracts
from my letter to Ms Henzell on the
packet radio network, with the same idea.
My thanks to both of these gentlemen for
their courtesy in advising their colleagues
of my actions.
In doing so, they along with Mr Bill
Roper VK3BR (former Federal Secre¬
tary/Manager of the WIA) also served to
remind me that most radio amateurs are
THE SERVICEMAN
decent, sensible and responsible spectrum
users, who don’t immediately launch an
intemperate personal attack on anyone
who is seen to disagree with them.
In short, they reminded me that the
much-vaunted ‘fraternity’ among radio
amateurs has not become a myth just yet
— despite the actions of a small minority.
And that’s where we’ll leave this rather
sorry tale, I think. I hope you’ll join me
here in the Forum next month, when
hopefully we can discuss something
more pleasant. ❖
Continued from page 49
soldered. All had been tinned but only
lightly crimped.
1 had brought my 25 watt 240V
soldering iron, but was kicking myself
for forgetting the small 300 watt 240V
Honda portable genset I usually take
for just such jobs. I couldn't solder the
lugs directly, as the soldering iron was
earthed and battery negative was also
earthed. This meant that the pins were
live. I jury-rigged the engine to run, then
disconnected the batteries. (At this stage
the internal 240 volt battery charger
wasn't working anyway).
After soldering all the connections, I
shut the generator down and reconnected
everything. Pressing the local start push¬
button now started and stopped the gen¬
set. So far, so good...
I tested the remote start by bridging
the contacts leading to it from the cir¬
cuit board at the generator. This again
started and stopped the unit, so I
called the owner and asked him to press
the button at the house. He did — and
nothing happened! I had already tested
the remote pushbutton at the house
and it was OK, so what was going on?
How embarrassing!
Dud cable join
Obviously, there had to be a break in
the 150 metres or so of aerial cable from
the house to the shed. Following along
the cable I spied a join at the highest
point (naturally!) and balancing on a
ladder, unwrapped it and found it badly
corroded. I accidentally bridged the
leads together while trying to repair the
joint and each time this started the gener¬
ator. In the end, / disconnected the
remote switch at the generator and fixed
the connection without further trouble.
After explaining to the owner the prob¬
lem with the cable, he said that some
weeks ago in heavy wind, the generator
was starting and stopping by itself during
the night! If only I had known that
sooner, I could have traced the fault
before I embarrassed myself...
Almost finished. The internal battery
charger hadn't worked for about 10
years, but I reasoned that it couldn't
be all that difficult. / rewired the primary
fuse, and turned it on.
Now, a 7.5kVA generator is a powerful
brute. Connecting a 25kW radiator to it
doesn't even cause a hiccup. A 5kW hot
water system causes the unit to slow
down a small but noticeable amount; but
in this case, connecting the battery
charger almost stalled the engine!
It turned out that the primary of the
charger transformer was a mess of
shorted turns. 1 suggested to the owner
that he connect a cheap six amp charger
to the batteries, to keep them topped up
until I could order another transformer...
And a final thought on the subject. A
strange characteristic of this engine is
that it needs 12 volts to open the fuel
cutoff solenoid, before it will start. This is
OK so long as the batteries can run the
starter motor. But to hand crank the en¬
gine in an emergency, the fuel solenoid
must first be held open with a suitable
bolt or nut to weigh it down. It seems to
be a poor design, to me.
Thanks for that story, Peter. It’s not a
bad thing for us city folk to be kept in
touch with the problems of providing
power to remote properties. There’s more
to supplying power than just pressing a
switch, as your story shows.
Well, that’s the end of the car-cum-en-
gine stories for the time being. As I said
earlier, there’s never been a subject that
excited as much interest — but next
month we’ll be back onto more mundane
topics. See you then? ❖
ELECTRONICS Australia, June 1995
73
Old power transformers
Last month, we related some experiences in the resurrection of a large 1930 model American
Columbia TRF receiver. However, as we ran out of space, the complex subject of dealing with the
power transformer had to be carried over until this month. As well as looking at transformer
rewinding, we also look at how to work out the voltage and current ratings required.
In the early days of radio, prior to the
early 1930’s, there were improvements to
be made in the design of power trans¬
formers. Wire sizes were often a bit on
the light side, and insulation (especially
enamel) had weaknesses. This was often
exacerbated by transformers in American
receivers having been designed for 60Hz
mains rather than our 50Hz, with the
result that there could be 20% less wire
and/or steel than conservative operation
called for.
Sometimes (and this was quite possib¬
ly the case with the Columbia) during at¬
tempts to fire up a receiver, the 240 volt
mains may have been connected to a
transformer intended for 110 volts.
Whatever the cause, the evidence of
melted pitch around the Columbia’s
transformer case was sufficient warning
that it was highly likely a rewind would
be necessary.
Why were the old transformers sub¬
jected to the messy business of being
buried in a box of pitch anyway? This
practice was not confined to power
transformers either. Frequently chokes,
audio transformers and capacitors were
treated similarly.
The major reason was protection
from moisture — but filling of chokes
and power transformers has another
benefit. Unless core laminations are
very tightly clamped, there is a chance
that they will hum and buzz, and in
some cases can be very hard to silence.
Encasing in pitch will silence practical¬
ly any laminated core.
A suitable sealant must have a
reasonably high melting point, be non
hygroscopic and inexpensive. Also it
must flow easily, so as not to leave voids
during filling. Although not a very attrac¬
tive material, pitch meets these require¬
ments quite well. In more recent times, it
was common for professional grade
transformers to be potted in a pitch based
ELECTRONICS Australia, June 1995
compound. Today, other materials such
as potting resins are used as well.
Difficulties
Whatever its virtues, when it comes to
dealing with a transformer that has
failed, pitch can be a frustrating ‘pain’ to
deal with. Not only can it be messy, but
the very properties that make it such a
good potting material also make it hard
to remove from a can.
In the past, many servicemen have un¬
derstandably sidestepped the problem by
simply substituting a stock replacement
transformer and throwing away the
original — thereby leaving a problem for
the restorer who demands authenticity.
Similarly, a rewinder can hardly be
blamed if he declines to rewind a trans¬
former embedded in a black gooey mess!
Some transformer rewinders do have ac-
Fig.1: As well as being somewhat
antisocial , using the kitchen oven for
exposing a pitch encapsulated
transformer is not completely
effective. There is still a tenacious
coating which is very resistant to
mechanical removal.
cess to Trichloroethylene vats or the like,
but most are likely to appreciate and
charge correspondingly less if they do
not have to perform the chore of cleaning
out the pitch first.
Therefore, a transformer in need of a
rewind may well have to be unpotted by
you. But to try and simply dig the wind¬
ings out of the can at room temperature
is a hopeless proposition.
One method is to arrange for the
family cook to go on holiday for a
couple of days and, when the coast is
clear, the transformer is suspended
for a few hours over a suitable con¬
tainer in the kitchen oven, heated to a
moderate temperature. This will melt
out the pitch, but unless there is an
efficient ventilating fan in the
kitchen, the smell can linger for a long
time — and bitumen is not flavour of
the month in most households. Further¬
more, the transformer is likely to be
left with a tacky black coating, typical
of that in Fig.l.
There is a better way. When very cold,
most grades of pitch become brittle, with
a consistency much like that of coal. The
cases of most filled transformers have
one side that is either open or removable.
This should be removed and the trans¬
former put in the coldest part of a deep
freezer for a few hours. The pitch may
then have shrunk sufficiently to allow the
contents to slide out of the can.
In any event, unless it is a very soft
grade, the pitch, will be sufficiently brit¬
tle to crumble readily with a few taps of
a piece of wood or a hammer, exposing a
relatively clean winding as shown by the
example in Fig.2. Any remaining traces
of pitch can be cleaned off with a petrol
soaked rag. Save the pitch, as it will be
needed later. The transformer can now be
packed off to your favourite rewinder.
Don’t forget to include as much informa¬
tion as possible.
74
For rewinders
This next section is directed mainly to
readers who are prepared to tackle, or are
involved in transformer winding. To
determine the specifications for a new
winding, the conventional approach is to
count the turns and measure the gauges
of the wires originally used.
For a proven design of transformer that
failed due to external causes this is the
correct method; but as pointed out
previously, American transformers
were frequently designed for 60Hz
mains supplies, and often had
110V primaries which, for con¬
venience in Australasian conditions,
may as well be replaced by a
230/240V winding.
Transformer design is quite complex,
but for satisfactory operation there must
be sufficient steel in the core and turns of
wire in the windings or the
transformer will be inefficient
and overheat. One vital
parameter governing the num¬
ber of turns is the magnetic
characteristics of the steel,
but this will generally not be
available. Fortunately a rule
of thumb has been worked
out that has proved satisfac¬
tory for most old cores.
Area of core
The critical parameter is not
the total amount of steel in the
core, but rather the cross-sec¬
tional area of the centre leg
which determines the number
of turns per volt. It has been
found that for a transformer
with the type of steel used
in old power transformers,
and operating at 50Hz, with
one square inch of core cross
sectional area, eight turns per
volt is satisfactory. (This al¬
lows for the thickness of the insulation
on the laminations etc., and I have used
imperial measurements as these were
usedinmostoldtransformers).
The formula is simply to multiply the
voltage of the winding by eight and
divide the result by the core area in
square inches. For example, a typical
old core with a centre leg of 2.0 square
inches, should have windings with a
minimum of four turns per volt.
Therefore a quick check is to count the
number of turns on one of the old wind¬
ings — say for example the 5.0 volt rec¬
tifier filament winding, and use the
formula (turns on winding/winding volt¬
age) x area of core in square inches. If
the result is less than eight, it would be
advisable to increase the number of turns
in the new windings. In most cases, espe¬
cially when using modem insulation, this
will not be a problem as the older cores
usually had plenty of window space.
A weakness of these old transformers
can be that of undersized wire for fila¬
ment windings. However, advantage
can be taken of the fact that many used
cotton-covered wire, and larger
diameter enamelled wire can be used
for the replacement winding occupying
the same space.
With the transformer rewound and
reassembled, and ready to be put back
into service, it is very tempting to wedge
it into its box without the hassles of
replacing the pitch; but unfortunately, to
do so is inviting trouble.
Enclosing a transformer in a relatively
airtight box will cause overheating. Air is
a very poor conductor of heat, and conse¬
quently air cooling of transformers is de¬
pendent on free and rapid air circulation.
Pitch is a much better heat conductor
than air, and readily transfers heat to the
surface of a case where it can be dis¬
sipated.
Refilling essential
If the original transformer case is to be
retained, there is therefore no option but
to refill it with pitch. This can be quite
easy. The melting point varies, but is
somewhere in the region 100 - 150°. A
large tinned fruit can is a suitable con¬
tainer and any reasonable source of heat,
including a gas barbecue can be used.
For my own workshop I picked up for a
few dollars a small used table-top electric
cooker, with a six inch hot plate and sim-
merstat control. The same safety precau¬
tions should be taken as with hot cooking
oil, and be careful not to overheat the
pitch, or there could be damage to the
transformer windings. Use only sufficient
heat for it to flow readily.
Extra pitch is likely to be needed to
replace inevitable wastage. One source
of supply would be roofing contractors,
but some time ago I obtained sufficient
to last me a lifetime by asking at the
local Municipal Electricity Department
store for some of the compound used in
underground cable boxes. I was given a
two gallon tin of what is really highly
refined pitch, perfect for the job.
What voltage?
Last month, I promised to explain how
I determined the HT voltage for the
rewound power transformer of the
Columbia receiver. While ex¬
perienced vintage enthusiasts
will be familiar with the proce¬
dures involved in calculating
the operating conditions of
receivers, newcomers may be
interested in the methods that I
used.
Radio manufacturers were
generally very coy about
publishing the HT winding
voltages of receiver power
transformers. There are
several likely reasons. One
was that 60 years ago, few
servicemen were equipped to
measure high AC voltages ac¬
curately. Another was that in
the highly competitive radio
industry, design knowledge
was valuable, and therefore
such information was what we
today call ‘commercially
sensitive’ — referred to then as
‘trade secrets’.
Many circuits did provide
valve pin voltages other than for the rec¬
tifier, and these are usually sufficient to
base calculations on. However, in the
case of the Columbia receiver, the circuit
provides no voltage clues at all and some
assumptions will have to be made. For
easy referral the circuit has again been
printed.
The first step is to estimate the likely
main HT voltage. Fortunately, it is not at
all critical and approximations are quite
sufficient. As the output stage valves nor¬
mally have the highest voltages, in this
receiver the HT supply to the anodes of
the 45’s is a good place to start. Refer¬
ence to early RIA tube manuals which
provide comprehensive data for these
valves shows their maximum anode
voltage is 275 volts, and give details
Fig.2: The same transformer after a spell in a deep
freeze. A few taps with a hammer shattered the brittle
coating and the residue was cleaned off with a petrol
soaked cloth.
ELECTRONICS Australia, June 1995
75
VINTAGE
for operation at 250 volts. There is little
merit in operating old valves at maxi¬
mum ratings, and an analysis of a num¬
ber of circuits indicates that a majority of
designers settled for 250 volts.
The anode or plate voltage ratings of
valves refers to the anode to cathode
potential, NOT anode to earth. In the
Columbia, as was the usual method, grid
bias for the output valves is derived from
the anode current voltage drop through
an 800 ohm resistor between the fila¬
ments and earth, and is given by the
Manual as 50 volts. This voltage, plus
the drop in the output transformer, must
be added to the anode voltage to arrive at
the HT figure.
The anode current of 62.5mA for a
pair of new type ’45 valves can be cal¬
culated by the simple formula Bias
Volts/Bias Resistor, or 50/800 =
0.0625. Assuming that the valves are
not brand new, a current of 30mA each
is quite close enough.
The resistance of each half of the out¬
put transformer was measured at
about 300 ohms, so that the voltage
drop in each side would be about 10
volts. Thus the main HT at point (A)
should be 310 volts.
RF stage operation
The next step is to estimate the
proposed operating conditions for the
RF stages. Their voltages are set by
the voltage divider formed by the
3000 ohm speaker field and the two
1500 ohm resistors.
Note that in these early sets, the
speaker field did not double as a filter
choke as became later standard prac¬
tice. The total resistance of the network
of the speaker field and the 1500 ohm
resistors is 6000 ohms, permitting a
current flow with 310 volts applied of
approximately 50mA, which would be
a reasonable amount of excitation for a
speaker of this type.
However, the current taken by the RF
amplifiers must be taken into account. To
achieve absolute accuracy, this becomes
quite complex as the valves themselves
constitute a dynamic load. We have a
roundabout wherein the current drawn is
dependent on screen voltage, which in
turn is dependent on the current through
the voltage divider and the volume con¬
trol setting — varying from practically
zero to 10mA or so.
The mathematics involved would be a
candidate for one of Peter Phillips’
‘What??’ puzzles.
Fortunately in practice, and because of
other factors such as valve ageing, vary¬
ing mains voltages, and component
tolerances, extreme precision becomes
academic. In any event, the heavy cur¬
rent through the speaker field and divid¬
ing resistors will have a considerable
stabilising effect.
Assuming therefore, that the current
for the RF stages under typical operation
is 5mA, the total current through the
speaker field will be 55mA. Added to
this is the 60mA for the output stage and
a nominal 5mA for the detector and
audio valves, to give a total HT current
of 120mA.
The voltage drop through the
speaker field will be .055 x 3000 =
165 volts, giving a voltage at (B) for
the anodes of the RF stages of 310 -
165 = 145 volts. It then follows that
as the screens are fed from point (C),
which is conveniently half way be¬
tween the anode supply point and
earth, they should have a potential of
about 145/2 or about 70 volts.
At full volume, with the extra current
drain, these voltages would fall slightly
to be very close to the traditional 135
volts HT and 67 volts for the screens —
figures very commonly specified for bat¬
tery powered receivers. This could be
taken as confirmation that the voltages
chosen are close. Although 24A’s can
be operated at higher voltages, it is un¬
likely that four cascaded stages would
remain stable if run at full ratings, and
it is likely therefore that our estimated
conditions are correct.
In any event, receivers are rarely de¬
pendent on precise operating voltages
and the heavy current through the volt¬
age divider masks the variations in the
currents drawn by the valves. For critical
situations, gaseous regulators were used
to stabilise voltages, but these were rare¬
ly used in domestic radios.
76 ELECTRONICS Australia, June 1995
WINDING TEMPERATURE
The operating temperature of transformer windings is important as it affects reliability
and safety. With standard class A insulating materials, the maximum allowable
temperature at any point is 105° C. Allowing for various factors, the maximum
temperature rise above ambient in a winding should not be more than 45 C.
With exposed cores, the time honoured rough and ready test is that if a hand can be
held on the core comfortably for 5 seconds, the temperature is satisfactory, but how can
a potted transformer be checked? The fourth edition of the Radwtron Designer s
Handbook in Chapter 5, Section 5 (v) describes a simple method of finding the
temperature rise by comparing the cold and hot resistances of the winding. Based on
the temperature coefficient of copper of 0.00393 the change of resistance can be
calculated using the formula.
R hot- R cold
Temperature Rise -
R cold x 0.00393
A correction should be made for any change in ambient temperature during the test.
As a practical example, the primary of a Majestic 90B pitch encapsulated power
transformer was tested. During a 5 hour run, the resistance rose from 10.1 a to ll.JU,
while the ambient temperature rose by T C.
Temperature Rise ■
11.3-10.1
10.1x0.00393
1.2
0.03969
= 30.23’
Subtracting the rise in ambient temperature, the operational rise was therefore;
30.23’ - 7" = 23.23°.
As this is well below a rise of 45’, the transformer in this example is quite satisfactory.
While touch is a commonly used gauge of temperature, it Is not very accurate,
and is obviously of little use for potted transformers. Here is a simple and more
precise methld which can be uked for any winding on any transformer.
Transformer voltages
We are now at the stage where the
voltage and current at the output of the
filter choke is 310 volts at 120mA.
The voltage drop in the filter choke is
the next calculation. As its resis¬
tance is 400 ohms, the voltage drop is
simply the current by the resistance;
0.12 x 400 = 48 volts, or 50 volts in
round figures. This is added to the 310
volts at the input to the speaker field to
arrive at a figure of 360 volts across the
first filter capacitor.
Now, at last, it is possible to determine
the transformer HT winding. Referring to
the Tube Data book again, and by read¬
ing off the graph for a capacitor input fil¬
ter for the type 80 rectifier, we find that
for an output of 360 volts at 120mA the
input to each of the rectifier anodes
should be 375 volts. The HT winding
specification is therefore 2 x 375 = 750
volts centre tapped, at 120mA into a
capacitor input filter.
The specification for the filament
windings is simply a matter of adding
up the individual currents. The main
filament winding supplies two type 27
and four type 24A, each 2.5 volts at
1.75 amperes or 10.5 amperes total! The
winding for the output stage feeds two
type 45 valves, each requiring 2.5 volts
at 1.5A. Finally, the rectifier filament
winding for a single 80 is 5.0 volts at 2A.
The transformer was duly rewound to
these specifications, with a gauge
heavier wire than used originally, but
with a 240 volt primary to suit local
conditions. As always, it seemed a bit
of a desecration to bury it in molten
pitch, but as we have seen, there was no
real alternative.
With the transformer installed, the
receiver was fired up, and the various
voltages measured. They all proved to be
very close to the calculated values, and
the receiver is performing well.
One of the great satisfactions of
vintage radio restoration is to have a
major project like this work out as in¬
tended. Somehow, filling a printed circuit
board with solid state components just
isn’t the same!
There is still a lot that can be written
about transformers and power supplies,
but as space has once more run out, we
will have to continue in the not too dis¬
tant future. *•*
WANTED
SURPLUS ELECTRONIC
COMPONENTS
ROCOM IS WILLING TO PURCHASE
YOUR EXCESS/OBSOLETE STOCK.
CONSISTING OF: SEMICONDUCTORS.
CONNECTORS, CAPACITORS, RELAYS
RESISTORS. ETC.
ROCOM ELECTRONIC COMPONENTS
261 Huntmgdale Road HUNTINGDALE VIC 3166
P.0. BOX 142 HUNTINGDALE VIC 3166
PH.61 3 548 9229 FAX. 61 3 562 8772
MOBILE. 018 564 085
| Audio-Radio j
[Valves & H’warej
\ New shipment power & j
pre-amp valves sockets j
retainers etc. Send SAE j
for free price/info list.
Also: parts circuits data
sheets technical advice
& custom construction, j
o
Z
o
DC
LU
O
<
LU
DC
Repairs to all valve
equipment.
(VINTAGE
WIRELESS
l LI H CCL
239 Australia St Newtown
NSW 2042
Ph: 02 557 2212
Fax: 02 516 3981
O
z
o
LL
Z
NOTES & ERRATA
NEW BOOKS (May 1995): In the review of
the Comprehensive Radio Valve Guide,
Books 1 -5, published by G.C. Arnold Part¬
ners, we inadvertently gave an incorrect tele¬
phone and fax number for ordering the books
directly from the publisher. The correct
number is 444 1202 658474, and the full
address is 9 Wetherby Close, Broadstone,
Dorset BH18 8JB, England.
EA READER INFORMATION SERVICE
BBS: Bob Barnes, of RCS Radio has created
and generously contributed a library of circuit
schematic symbols which allows convenient
use of Protel's freeware PCB drawing package
EASYTRAX for drawing schematic diagrams
as well. You’ll find the library, together with
its documentation and a ‘PCB’ file showing
the symbols in A4 chart form, on the BBS in
the Technical Software file area, as a com¬
pressed file named EZSCHEM1.ZIP.
mvc JUNE BARGAINS FROM J AYnAa m
ims
L"l^» mm Was reviewed in _ Inics
13 — — £25 AIIQTBAIIA JV80 8" SUBWOOFER ,NCS
JAYC
JAYC
! AUSTRALIA
™ JUNE 1995
The driver used in this subwoofer is the fabulous new Vifa
M22WR 8” driver. It incorporates a long stroke, low
reflection magnesium basket, has a 50mm voice coil and
a very stiff conical paper cone with a low damping rubber
surround. Power handling is an amazing 150WRMS.
Please contact us for a copy of the article from
Electronics Australia if you don’t have it.
The cabinet is supplied prebuilt and is made from
MDF in blackwood veneer. Grill is
supplied with speaker cloth
mounted. Cabinet size is very
small, with a volume of 35
litres, and measures 600 x 270 x
300mm. We recommend a
polyswitch speaker protector to help
protect the driver.
Check with your local Jaycar store for a demo. Demos in
most stores.
Speaker - Vifa M22WR Cat. CW-2115 $199.50
Polyswitch Cat. RN-3472 $10.95
Cabinet Cat. CS-2540 $139 .00
Totg[$349.45
Quote from Rob Evans in
Electronics Australia Magazine.
“The JV80 performed extremely well in both our
subjective and objective tests, and really did
demonstrate how a refined driver such as the Vifa
M22WR can deliver the goods in a correctly tuned
enclosure”.
[Save' On ProfessJonaf QuafitFOFC
; Reference Series RCA Leads
i These Reference Series use OFC »-—•
| shielded low capacitance cable with
i a central lead wire for remote
j switching of car amps, or for extra
I grounding on home Hi Fi. Cable is
i figure 8 OFC blue colour with an OD
i °f 5mm per side. Plugs are superb
i quality gold with nickel metal covers.
J £ sch lead is colour coded with red
i and black RCA plugs. Each lead has
j two RCA plugs on each end.
i S&ftdifigatigns:
j ‘Material: Oxygen Free Copper
, ^Stranding: 10/0.t2mm
i ♦Shield type: Spiral
| ^Ground wire: 10/0.12mm
i ‘Capacitance: 68.8PF/M
j 64K DATABANK
Features: »64K memory
•Databank ‘Real time clock
•Calendar •Calculator *Currency ^
conversion *Data communication available
plus more. See our 1995 catalogue page 183 for
further details. Smaller models also available.
Cat. QM-7320 $129.50
PC INTERFAOF
Cat. QM-7324 $39.50
•Size: 0.40mm
•Diameter: 0.75mm
•Standard: 45/0.12mm
•Resistance: 0.0385Q/M
. , ltB; oo.oKr/M •Impedance: 6512 at 1 MHz
0 5 metres was $19.95 June $14.95 Save $5 CatWA
J J1J metres was $24.95 June $18.95 Save $6 Cat WA
$27.95 Save $7 CatWA
PRO RACK CASE
SELLOUT
. . S’; w' T 5 i
* • a r ¥
<*» T V * 3 * ~ v 1 •
*1060
1062
•1066
ESpri:
CAR -r i
VOLTAGE f~
METER / l_ .
CLOCK / J
STOPWATCH NEW
Features: .Automatic 12/24V selection .Digital readout for battery
voltage *Lap counting ‘Stopwatch for sports ‘Digital clock 12/24
hour selectable ‘Backlit ‘Small size 115(W) x 27(H) x 15(D)mm
Cat. XC -0118 Only $29.95
Save money on our grey professional
_. rack cases. See our 1995 catalogue
J page 121 for full details.
Cat No. Was
1 unit HB-5120 $75.00
2 unit HB-5125 $99.50
3 unit HB-5130 $109.50
SAVE ON BENCH
ENCLOSURE
See our 1995 catalogue page 120
Size 132(H) x 279(D) x304(W)mm
Cat. HB-5570 was $59.95
NOW $44.95
SAVE $15.00
Now
$59.00
$79.50
$89.50
Save
$16.00
$ 20.00
$ 20.00
JAYCAR
JAYCAR
JAYCAR
JAYC -
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A
A
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ELECTRONICS JAYCAR
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ABS PLASTIC BOX
Made in the U.K. from ABS. Has a precision
fitting moulded lid with metal bushes to take
countersunk screws (supplied). Its about the
same size as the largest size Jiffy Box.
Measures 190(L) x 110(W) x 60(D)mm. Jiffy
box sells for $6.75.
BUY THESE FOR ONLY $3.95 EACH.
Normally sells for around $12. Colours available: white, blue and orange.
Cat. HB-5504 Only $3.95 ea
D-SLB SPEED CONNECT
DATA POBT
Another surplus buy. Made in the U.K. These
ports provide the user/installer with a simple
system for installation of “D" connectors. The IDC
feature eliminates soldering, and wires can be quickly disconnected - _TTJT-_ i
and rewired to new pins if required. Inserting wires is made easier
you have a BT inserter tool. Faceplate is UK power point size ie 85 x - ^ 1
85mm - white in colour. Fitted with 2 x D25 females. LIMITED QUANTITY AVAILABLE.
Cat. PP-0859
at PP^0859_ only $5 eaj
ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS
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Save $30 On Car Speaker Kit ^
The system consists of 6.5"
woofer, and a Neodidyium ^
Super Tweeter with a high
power crossover. They | ( ^ ■ I
handle high power, so ^ ■ ]Z. 1
require a power amp of at _ I
30WRMS per channel
to drive them properly. 10
watts is not enough!
SPECIFICATIONS:
•Power handling - 80WRMS/240W PMPO -Impedance - 4 ohms *Freq
resp - 50 to 22,000Hz -Sensitivity: 90dB 1 watt 1 metre -Resonant frequency
(fs): 50Hz -Sound pressure level - 90dB -Woofer - 6.5" with treated paper
cone and rubber surround, magnet weight -10 ounce, voice coil dia 25mm
•Tweeter - Super tweeter with surface mount design. Small size with great
response -Crossovers - High power units with crossover frequency of
2500Hz. Each housed in its own case.
Supplied with metal grills for woofer and mounting screws/cables etc. A
quality set of speakers that will give you years of excellent service. Add to this
a Subwoofer for excellent car Hi Fi sound.
Cat CS-2275 was $199.50 pr JUNE $169.50 PR
75ft WALL SOCKET PLATE
BARGAIN
These have
a standard
75 ohm
socket in the centre of a square
plate. They are not the
standard power point size, but
they are cheap!
Plate size: 85 x 85mm. Colour white.
cat. lt-3028 only $2 ea
TELEPHONE
PLUG 8/8
RJ45 SPECIAL
ATTENTION COMPUTER
INSTALLERS
These are NOT AUSTEL APPROVED.
We are selling these in bags of 50
pieces. Save a fortune over normal
prices.
NORMALLY AROUND $1.00 EACH
Cat. PP-1436 $1 7.95 pKt 50
50 PIN CENTRONICS/SCSI
CONNECTORS
Right angle entry,
complete with metal
backshells.
Cat. PP-0891 Male
$3.95
Cat. PS-0899 Female $3.95
BUY 10
Save On Interlocking Parts Drawers
Unique side and top/bottom keying system allows
you to use just a few or build a whole wall of
drawers as your parts expansion dictates. Quality
designed drawer slides will not ‘stick’ or seize. Slide
handles also takes identity cards. Single or double
drawers available.
Size: 110(W)x 120(D) x50(H)mm
SINGLE DRAWER Cat. HB-6300
Normally $5.95
JUNE $4.75 or 10 FOR $40
6 UAL DRAWER Cat. HB-6301
Normally $6.20 JUNE $5.00 or 10 for $45
Clock
Movement
•Very compact 56 x 56 x
15mm -Self starting one
second stepping motor-Uses
1 x AA battery that lasts 1
year -±15 second/month
accuracy -Supplied with three
sets of hands -Includes
sweep second hand
Cat. XC-0100
300VAC VARISTOR BARGAIN
Specifications: •Dia:7mm
•RMS Volts: 300 *DCV: 405
•Joule: 25 *Peak Current: 1200A
•Capacitance: 70pf
Cat. RN-3402
$1.50
Tamper Proof
~' Torx Screw Bit Set
The set consists of 7 Tamper Proof Star pieces
which fit the 6 point STAR type screws with
tamper proof pins, as those found on computer
systems etc. They are T10, T15, T20, T25, T27,
T30, T40. Made from chrome vanadium - steel
and heat treated.
Cat. TD-2034
0.45 VOLT 10OOIHA
SOLAR CELL SPECIAL
Ideal for experimentors. Connect in series or parallel.
Terminal strap enables easy connection to other cells.
Cat. ZM-9004
normally $7.50
JUNE ONLY $4
SAVE $2.55
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PROBES WITH
25IVIHZ CRO
PURCHASE
The Jaycar 25mHz Dual
Trace CRO leatures
delayed sweep. Most
other CROs are 20mHz.
our is 25mHz. See 1995 catalogue page 35 for details and specifications.
Cat. QC-1900 only $7 49
June - 2 probes supplied free, value $79 Kjjcs J
CS
cs
CS
cs
cs
cs
cs
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NICS J
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JAYCAR
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ELECTRONICS JAYCAR
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E
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Playmaster 300W Subwoofer >
Amp Kit
NEW
REF: ELECTRONICS AUST
APRIL/MAY 1995
Cat. KA-1770
$349
f - • ■. it/.
A
Mini Spot AM/FM
Alignment ■ Source
Kit
Digital THgger
Adaptor Kit For
CRO’s
REF: EA 4/95
This project allows you to'use your CRO more effectively with digital circuits by
allowing you to monitor any given event in the circuit under test, and to trigger the
scope only when all the relevant input conditions are met. With eight inputs
(expandable to 24), it also includes an adjustable trigger delay, so it can effectively
convert your scope into a low cost logic analyser. Kit is complete with PCB, case,
screen printed front panel, 1C test clips plus all electronic componerte.
Cat. KA-1772 555.00
I Ifl[DOLBYBUHHOUNPj
PRO • L O O I C
- _ fL - 4 _ "
Economy Surround Sound _
Decoder Kit
REF: EA 5/95
This surround decoder uses
low distortion analogue
circuitry to produce a surround
channel, centre channel and
subwoofer output channel. If
our genuine Dolby Pro-Logic
decoder (KC5175) is out of
your price range, then this
economy decoder is worth
considering. The Jaycar kit is
100% complete with case,
PCB, punched & silkscreened front panel, punched rear panel,
transformer, RCA sockets plus all elec components as per the EA article.
Cat. KA-1773 $59.50
l svfmovw sound DBcooen
REF: EA 4/95
This kit will provide both a
455kHz signal for aligning AM radio IF strips and
a 10.7MHz signal for doing the same job on FM
radios. Both signals are modulated with an audio
tone of around 1 kHz, with the 1 kHz audio signal
available by itself for audio testing. The Jaycar kit is complete with PCB, case, silk
screened front panel, plus all electronic components. Three AA penlight batteries required.
Use Cat. SB-2354 Pk4
Cat. KA-1796 $23.95
Dolby Pro Logic Surround Sound Kit
REF: SILICON CHIP DEC 94 / JAN 95
Short Form Kit
This kit is
supplied with
pre-tinned
PCB, Dolby
ICs and all
electronic
components
as per the
Silicon Chip
article, RCA
socket bank,
potent¬
iometers,
switches and
internal
audio and
mains cable. The short form version of the kit is ideal for those constructors who wish
to build a complete decoder with amplifier modules in the same case as the decoder.
EXCLUSIVE TO JAYCAR.
$169.50
Cat. KC-5175
Enclosure Kit
This includes the low radiation toroidal transformer, mains lead and plug, fuse holder
and fuse, mains switch, black anodised brushed aluminium instrument knobs,
professionally punched and screened front panel, punched rear panel plus all
mounting hardware.
Cat. KC-5176 $69.50
JAYC
JAYC
u A Listeners Guide To Dolby
j Surround Book
i If you are planning a home theatre for your
I home, then this guide is essential. It covers all
aspects of what you need to set up, and get the most out of a
home theatre system. Topics covered: 'Speaker placement
•Subwoofers 'Surround and centre channel speakers 'Power
irs all
amplifiers 'Enhancements for movie viewing - plus much more!
„ This book will answer virtually any question you may have
K regarding Pro Logic Surround Sound. Don't be left behind - the
home theatre revolution is here! 11 pages with fully illustrated
““ pictures. Size: 210mm x 295mm.
ALARM PANELS
Cat. BC-1200
only $2.95
Low Cost Temperature Controlled Soldering Iron
4500 4 SECTOR PANEL
Cat. LA-5420
$ 109.50
6000 6 SECTOR PANEL
Cat. LA-5430
$ 139.50
•Programmable *24 hour
tampers 'walk tests •intelligent
auto rearm 'plus more
See our 1995 catalogue for full
details
Ideal hobbyist soldering station. It
operates on 240 volts, and the
transformer delivers a safe 16
volts to the soldering iron.
It has a PTC (Positive
Temperature Coefficient)
fl soldering tip at a constant
temperature of 310°C which is ideal for PC
work. It has a 20 second heatup time.
Replacement Tip Cat TS1202 $9.95
Cat. TS-1200
JAYCAR WILL NOT BE UNDERSOLD ON
PRODUCTS OF THE SAME QUALITY
WAS $49.95 NOW $35.00
D41 264C-1 5
NEC BRAND - LIMITED QTY AVAILABLE
Cat. ZZ-8520 only $8.95 ea
JAYC
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JAYC
A
A
A
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A
A
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and huge magnets
and the other with
WOOFERS / SUB WOOFERS
See our 1 995 catalogue, or call for full details.
Now available with single voice coils. All these drivers
have 8 ohm voice coils and have rubber surrounds
. Two ranges available, one with polypropylene cones,
carbon fibre cone.
Size
Cone
Power
Box Size
Cat
Inch
Material
Handling
Vented
Sealed
No.
Each
6"
Polycone
80RMS
26LT
10LT
CW-2135
$55.00
6"
Carbon Fibre
80RMS
24LT
15LT
CW-2140
S79.50
8"
Polycone
120RMS
33LT
27LT
CW-2136
S69.50
8"
Carbon Fibre
120RMS
25LT
20LT
CW-2142
$115.00
10"
Polycone
160RMS
50LT
32LT
CW-2137
S109.50
10"
Carbon Fibre
160RMS
65LT
33LT
CW-2143
$169.50
12"
Polycone
200RMS
120LT
80LT
CW-2138
$149.50
12"
Carbon Fibre
200RMS
116LT
76LT
CW-2145
S209.00
DUKE SPEAKER KITS SLASHED
See 1995 catalogue page 47
QK77 SPEAKER KIT
Features 2 x 6” woofers, dome mid and dome
tweeter. Power handling 120WRMS
SPEAKER KIT (PR) Cat. CS-2530
WAS $399PR NOW S299PR
SAVE SlOO
DK77 CABINET Cat. CS-2532
WAS $290 PR NOW S250PR
SAVE $40
PK11 SPEAKER KIT
6” bass and dome tweeter. Power handling 60WRMS
SPEAKER KIT (PR)
Cat. CS-2520
WAS S229PR
NOW S159PR
SAVE $70
CABINETS TO SUIT DK11
Cat. CS-2522
WAS S170PR * e *loi4,
NOW S140PR
SAVE S30
PLASTIC “LINE TYPE” CASE
□
This case is new, but contains
components which were removed, it
consists of two halves of hard and hi*
impact plastic held together by 4 self
tapping screws. The box measures 88L x 68W x 55Dmm. |
In the middle of each lid is a small rectangular hole
measuring 10 x 7mm. It is ideal for an in-line power supply or some sort of
interface. It is well made and quite rigid. It would also
make a cheap general purpose small enclosure. A
redundant manufacturers identification panel appears;;
on one side of the case. Even a low cost jiffy case of
similar size would cost about $3.00. This box is better |
quality at half the price.
Cat. HB-6080 A great buy for the Junk bin
i
1
,
I
1-4
$1.50 ea |
5-9
$1.35 ea j
10+
$1.20 ea j
CHEAP 12V POWER V*
The more power you need, the more you save! Yes, yet^^BM^
another massive scoop purchase. This time its a 240V HE
to 2 x 12VAC (at 1 amp) chassis type tranny. We say SHfe
chassis type, but the tranny itself has no strap bracket m
like our standard chassis-mount unit. You can make a
strap bracket for these out of a jiffy box lid or, as many do
nowadays simply hold it down with a couple of medium ^
cable ties. If you don’t have a problem with the mounting you >>
will save a fortune! Normally, you would expect to pay about Si 6
for a 2 x 12VAC 1A tranny BUT NOT THIS TIME!!! We-
have a fairly solid quantity of these little beauties
and we are keen to sell!! Our price is therefore
reflected in the quantity you buy. Each tranny has
primary and secondary leads abot 300mm long and
are colour coded. Great for +/-12V DC supplies 12V
at 2A etc. Grab a few for the parts box!
Cat. MM-2000
TRULY A BARGAIN
.00 ea
.25 ea
.95 ea
.65 ea
.50 ea
naycar
— ELECTRONICS
HEAD OFFICE
6 LEEDS ST RHODES 2138
PHONE: (02)743 5222
FAX: (02)743 2066
WHOLESALE
PHONE: (02) 743 5222
ORDERS: 1800 620 169
FAX: (02) 743 3070
MAIL ORDERS
PO BOX 185 CONCORD 2137
ROAD FREIGHT ANYWHERE
IN AUST (up to 20kg) $14.00
MAIL ORDER - PHONE
FREE CALL- ORDERS ONLY
(008) 022 888
HOTLINE (02) 743 6144
POST & PACKING
$10-$24.99 $4 00
$25 - $49.99 $5.00
$50 - $99.99 $7.00
OVER $100 $8.00
JAYC
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JAYCAR ELECTRONICS JAYCAR
JAYCAR ELECTRONICS JAYCAR
ADELAIDE SA *194 Wright St (Cnr. Selby St)*Ph:(08) 231 7355
•Fax:(08) 231 7314*Mon/Fri:9-5.30*Fri:8.30*Sat:9-12pm
BURANDA QLD *144 Logan Rd*Ph:(07) 393 0777*Fax:(07) 393 0045
•Mon/Fri:9-5.30*Thurs:8.30*Sat:9-4pm
CANBERRA ACT *11 Kembla St. Fyshwick*Ph:(06) 2391801
•Fax:(06) 239 1821 *Mon/Fri:9-5.30*Sat:9-1pm
COBURG VIC *266 Sydney Rd*Ph:(03) 3841811 •Fax:(03) 384 0061
•Mon/Fri:9-5.30*Fri:8.30*Sat:9-4pm
MELBOURNE CITY -Shop 2,45 A’Beckett St*Ph:(03) 663 2030*Fax:6631198
•Mon/Fri:9-5.30*Fri:8.30*Sat:9-2*Sun:10-4pm
SPRINGVALE VIC *887-889 Springvale Rd Mulgrave. Nr Cnr. Dandenong Rd
•Ph:(03) 547 1022*Fax:(03) 547 1046
•Mon/Fri:9-5.30*Fri:8.30*Sat:9-4pm
SYDNEY CITY
BANKST0WN
GORE HILL
NEWCASTLE
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ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS J<
ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS J,
*129 York St*Ph:(02) 267 1614*Fax:(02) 2671951
*Mon/Fri.8.30-6pm*Thurs:8.30pm*Sat:9-4pm
*363 Hume Hwy Cnr Meredith St*Ph:(02] 709 2822*Fax:(02)709
2007*Mon/Fri:9-5 30*Thurs:8.30pm«Sat:9-4«Sun:10-4pm
*188 Pacific Hwy (Cnr. Bellevue Ave)*Ph:(02) 439 4799*Fax:
(02) 439 4895*Mon/Fri:9-5.30*Thurs:8.30*Sat:9-4*Sun:10-4|
*830 Hunter St *Ph:(049) 653 799 *Fax:(049) 653 796
►Mon/Fri:9-5.30 *Sat:9-4pm
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►Fax (02) 683 3628 • Mon/F ri :9-5 30*Thurs:8.30pm»Sat:9-4pm
►Sun:10am-4pm
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I
■ IAW AVA1 9 ■ ■
NEW BOOKS
Fault libraries
TV FAULTS and VIDEO FAULTS,
Sixth Editions 1995, published by
Technical Applications. Plastic comb
binding, 300 x 210mm, 218 pages and
196 pages respectively. Both fault li¬
braries available alternatively as data¬
base files on an IBM-compatible
floppy disk, along with a program and
also a camera/monitor database.
Printed libraries $90 each or $165 per
pair, or $160 on floppy disk, including
postage anywhere in Australia.
The lot of domestic electronics service
technicians is getting harder and harder
all the time, with equipment not only
getting more complex and sophisticated,
but also more reliable — so that you tend
to have less opportunity to become fa¬
miliar with both the gear and its faults.
Not only that, but customers are nowa¬
days much less happy than in the past
about paying for what is inevitably a la¬
bour-intensive activity, especially if their
TV or video is a few years old and lacks
some of the ‘bells and whistles’ of the
latest models...
Small wonder, then, that more and
more technicians seem to be turning to
the use of compiled ‘fault lists’ or data¬
bases, as an aid to finding faults faster
and more efficiently. While such lists
won’t always provide the exact cause of
a particular fault, they can at least help
you quickly rule out the more common
causes, leaving more time to track down
an unusual and hard to find fault.
Keith Jakins, the proprietor of Queens¬
land firm Technical Applications, has been
compiling and supplying his valuable TV
and Video fault libraries for some years
now, and has just released them in these
updated sixth editions. Together they now
cover over 10,000 different faults, in mod¬
els widely sold in Australia.
Not only that, but each fault library
comes with an accompanying and very
useful model cross-reference list, to al¬
low identification of the models (often
quite a few of them) which either share
virtually the same chassis, or differ in
only minor respects. The cross-reference
list in the TV Fault library is 25 pages
long, while that in the Video Fault library
is six pages long.
Both main fault libraries assume that you
have a service manual or at least a sche¬
matic for the set concerned, making exten¬
sive reference to the maker’s component
ID reference labels. They also tend to use a
lot of service tech shorthand terms, such as
‘LOP’ for line output transformer, ‘D/J’ (or
‘D.J.’) for dry joint, and ‘NSNP’ for no-
sound-and-no-picture. Although this
would probably make them rather too
cryptic for anyone other than service
tech’s, these are after all the people they’re
intended for, anyway.
I did note quite a bit of inconsistency,
though — like H/OPT, LOP, L/OP, LOP-
TXER and FLYBACK TRANSF (all re¬
ferring to the line or horizontal output
transformer), and a few spelling errors. I
gather that these reflect the differing ori¬
gins of some of the fault/cure items, many
of which come from clients in the form of
update contributions. (Technical Applica¬
tions provides updates twice a year, for
$30, but gives discounts for contributions.)
The computer program version of the
libraries is integrated, with both main da¬
tabases and the additional ‘appliance’ da¬
tabase accessed via a single main menu.
They come in compressed form on a
high-density floppy disk, with a program
to install them on your hard disk along
with the viewing program.
The sample libraries installed very easily
■
■
■ TV FAULTS
on a 286/12MHz machine, and using them
in this form is certainly very fast and con¬
venient. You need to print out the model
cross-reference lists, though, to facilitate
rapid access to the right chassis model.
All told, then, my impression of the
Technical Applications fault libraries is
that in either printed or program form they
should be of value to any service techni¬
cian involved in TV and video work.
The libraries are available direct from
Technical Applications at PO Box 137,
Kenmore 4069; phone (07) 878 1352, or
fax (07) 378 1064.
Microprocessors
ADVANCED MICROPROCESSORS,
by Daniel Tabak. Second edition 1995,
published by McGraw-Hill. Hard
cover, 155 x 235mm, 523 pages. ISBN
0-07-062843-2. RRP$160.
This book is not just a guide to today’s
microprocessors; it’s about all types of
microprocessors, including chips like the
Intel Pentium, the PowerPC, the Super-
SPARC and the 68060 from Motorola.
It starts with an overview of micro¬
processor (uP) development and goes on
to describe the general structure of a uP.
Memory hierarchy and pipelining are
each given a separate chapter, which
leads to a discussion of RISC uPs. Then
follow chapters on the Pentium and ear¬
lier Intel 80xx chips; the Motorola 680x0
family, the 68060 and 68040 and the ear¬
lier 68000 uP's; Advanced RISC Micro¬
processors; the DEC Alpha AXP; the
PowerPC family; the Sun SPARC; the
MIPS RxOOO; the Intel i860; the Mo¬
torola M88000 and the HP Precision Ar¬
chitecture families. The last section is
about developing a microcomputer,
where the author explains how to go
about designing a system best suited to
your needs.
The book contains listings of instruc¬
tion sets, programming models and many
block diagrams, and the writing style is
concise and to the point. It’s not a book
for beginners, but anyone serious about
microprocessors will find it informative,
and (at the time of writing) about as up-
to-date as you can get.
The review copy came from McGraw-
Hill, PO Box 239, Roseville 2069. It
should be available from technical and
larger bookshops. (P.P.) ❖
82
ELECTRONICS Australia, June 1995
SHORTWAVE
LISTENIHGM
with
Arthur Cushen, MBE
BBC monitors the world for news
Shortwave listeners not only find enjoyment
in the entertainment field, but their listening
brings them news from all over the world.
This type of information gathering has been
long established by the BBC, which has
operated in this field for some 55 years. Today
transcripts of radio and television broadcasts
from over 140 countries in 70 languages are
combined with news agency reports, in a ser¬
vice which operates 24 hours a day every day
of the year.
The BBC monitoring station at Caversham
Park, located west of London, has just com¬
pleted a £1.5 million investment in upgrading
its equipment. The station has made increas¬
ing use of remote receivers located around the
globe, to hear local AM or FM programmes
which normally would not be heard
thousands of kilometres away. Any one of the
100 receivers at Caversham Park, where the
monitors listen to the broadcasts, can select
one of 32 aerials located some 8kms away.
The remote receiving sites include Helsinki,
Stockholm, Warsaw, Prague, Vienna, Kiev,
Kuwait, Teblise and Pershawa, as well as in¬
formation gathered from BBC correspondents
scattered throughout the world.
The comprehensive nature of the informa¬
tion coming into the monitoring service is
reproduced in various publications, including
the World Broadcasting Information publica¬
tion which is issued each week, highlighting
the changes which have been noted in fre¬
quencies, languages and transmission times
from stations all over the world. The BBC
would rank as the largest monitoring service
in the world, closely allied to the Foreign
Broadcasting Information Service of the
United States.
The early days of the BBC Monitoring
Service were devoted to enemy propaganda
and broadcasts, and much of the world's
news on allied stations was supplied from the
BBC monitors.
The 1947 BBC Yearbook indicated that
there was a new role for the Monitoring Ser¬
vice, as the war years had shown clearly its
value as a source of foreign news for the
benefit of the Home, Overseas and European
news bulletins of the Corporation — and
also as a reservoir from which the editors
of bulletins and compilers of programmes
for listeners abroad could draw back¬
ground material.
The first requirement of an efficient
monitoring service is a good reception site,
where the maximum number of radio signals
can be intercepted. The monitoring receiving
station at Crowsley Park in Oxfordshire has
been found almost ideal for this purpose,
since it provided adequate land over which
the most efficient aerial systems could be
erected. It was also well removed from any
residential area and public roads, which pro¬
vide a source of electrical interference.
Some 10 years later the BBC Yearbook
reported that the experience gained during
and after the war amply confirmed the value
of monitoring as a rapid and often unique
source of information. Most Governments and
broadcasting organisations throughout the
world have since found it essential to main¬
tain some parallel form of service.
In this continuing and complex task, the
BBC Monitoring Service works in close
cooperation with its American counterpart,
which under a reciprocal agreement provides
monitored material from the Far East and
other areas inaudible in Britain.
Today the Monitoring Service is a vital
component in news gathering. Readers of
this feature will be aware of the informa¬
tive nature of shortwave listening, when they
can access news and information from foreign
broadcasting stations much quicker than by
any other source. ❖
AROUND THE WORLD
BELGIUM: Brussels Calling, in English is now broadcast from 0630 -
0700UTC on 6015 and 9925kHz to Europe, and on 9925kHz to
Australia; 0900 - 0930 on 6035, 15,545 and 17,595kHz to Europe and
Africa; 1800 - 1830 on 5910 and 13,685kHz; and 2100 - 2130 on
5910kHz; and 2230 - 2300 on 9925 and 13,800kHz.
This is only part of the schedule and the DX programme is heard on the
Monday transmission.
ECUADOR: HCjB, Quito, has re-timed its DX Partyline to the South
Pacific and it is now heard on Saturday at 0908UTC, after the
news on 6135kHz.
The broadcast to Europe is from 0700 - 0830 with DX Partyline heard
at 0738 on 6205. The SSB test continues on 21,455kHz and the power
is now 1500W. The station is keen for reception reports, sent to: The
Frequency Manager, HCjB, PO Box 17-17-691, Quito, Ecuador.
GUAM: KSDA is to use a lOOkW transmitter beamed on a bearing of
345 degrees to test to Papua New Guinea and Northern Australia, get¬
ting the back beam, up to Saturday 24th June from 0900 - 1000UTC on
9530kHz. A new DX programme called Wave Scan is heard in the
Sunday session. A new verification will be issued for reports.
HUNGARY: Radio Budapest has broadcasts in English to Europe 2000 -
2030UTC and 2200 - 2230 on 3975, 6110 and 7220kHz; to North
America 0200 - 0230 on 6025, 9835 and 11,910kHz, and 0330 - 0400
on 5964, 9835 and 11,910kHz.
INDIA: All India Radio, Delhi has English to the Pacific, 1000 -
1100 on 15,050, 15,180 and 17,387kHz; and 2045 - 2230 on 9910,
11,715 and 15,225kHz.
INDONESIA: RRI, Banda Aceh has been heard at 0900 with Indian
chanting on 3905kHz and covers the Papua New Guinea station, Radio
New Ireland at this time. The RRI station is now 50kW.
NEW ZEALAND: RNZI has a new schedule effective up to the 30th of
September: Monday - Friday at 1650 - 1849 on 6145kHz; 1850 - 2050
on 11,910kHz; 2051 - 0458 on 15,115kHz; 0459 - 0716 on 9570kHz;
and 0717 - 1206 on 6100kHz. At the weekends opening and closing
times vary.
TAIWAN: Taipeh's Voice of Asia has been heard on 9280kHz at
1000UTC with multi-language announcements including English.
The programme is in Chinese and is of a Gospel nature. At
1100UTC WYFR's interval signal is heard and carried on the frequency,
still in Chinese.
UNITED KINGDOM: The latest schedule for the BBC World Service to
the Pacific, effective up to September 24th, is:
0500 - 0800 on 15,360kHz; 0900 - 1030 on 15,280kHz; 0500 - 0900
and 1800 - 2400 on 11,955kHz; 2200 - 2300 on 11,695kHz; 1130 -
1615 on 9740kHz; 1830 - 2200 on 9740kHz; and 1100 - 1130 on
6100kHz.
Radio Australia on 11,695kHz and RNZI on 6100kHz are the relays in
this area. Early predictions indicated Russian interference may be noted
on 9740kHz during the first period of transmission.
VATICAN: Vatican Radio has been heard now using 4010kHz in
English at 1615 and Italian at 1630. The interval signal is heard
at 1700UTC.
ZIMBABWE: Christian Voice has been heard with test broadcast at
0450UTC in English using 4965, 6065 and 7250kHz. The station is
also testing at 1830 on 4965kHz. ❖
This item is contributed by Arthur Cushen, 212 Earn Street, Invercargill New Zealand who would be pleased to supply additional information on medium and
shortwave listening. All times are quoted in UTC (GMT) which is 10 hours behind Australian Eastern Standard Time and 12 hours behind NZ Standard Time.
ELECTRONICS Australia, June 1995
83
Information centre
Conducted by Peter Phillips
Party pieces, magnetics and high voltage caps
There’s quite a range of information this month, including details of how to modify K3A and K9A
Philips TV receivers to work with a VCR. A reader makes a few comments about the March What??
question, there’s discussion on capturing lightning, and we give details of an ELF/VLF electric field
meter.
This is the part of the magazine where
we include anything we think useful, in¬
teresting or even entertaining. For this
reason, you never quite know what the
column will contain. In line with this
philosophy, this month I’m including a
number of letters that are not strictly
about electronics, but nonetheless inter¬
esting. Of course, there’s also letters
about electronics. A reason for doing this
is that I was reminded recently at a
gathering that while electronics is a fas¬
cinating and engrossing subject, it
doesn’t give much food for social inter¬
course. Start talking about the latest
microprocessor at a 21st birthday party,
and watch people’s eyes glaze over!
Over the years this column has
covered some pretty wide-ranging
topics, including a few that even the
technically illiterate would find interest¬
ing. It’s some of these that I’m drawing
on to give you some party pieces, like
this one...
Which side?
I’ve just been reading your Informa¬
tion Centre pages in the March edition of
EA. As usual some entertaining and in¬
formative reading, for which I thank you.
Under the heading of Blue Lights, you
make mention of Henry Ford and the
American left-hand drive. In a recent
book called Made in America, by Bill
Bryson, another reason is given why
American drivers sit on the left.
The author writes about a form of
horse-drawn transport known as Cones¬
toga wagons. He says: “An unusual fea¬
ture of Conestoga wagons was that they
were built with their brakes and ‘lazy
boards’ (a kind of extendable running
board) on the left hand side. If there is a
particular reason for putting them there,
it has long since been forgotten. With
drivers compelled to sit on the left, they
tended to drive on the right so that they
were positioned near the centre of the
road, which is why it appears Americans
abandoned the British custom of driving
on the left. (Barry Freeman, Morphett
Vale, SA.)
Thanks for this bit of trivia Barry, and
thank you for your kind comments. It
seems reasonable that the decision to
drive on the right was the result of
popular practice. However I’m sure I’m
not alone in wishing the Conestoga
wagon (if it’s the reason) had been
popular in other parts of the world. I
have no preference for what side we
drive on, but it would be nice if every
country did the same.
Gross or Grob?
If you were studying electronics in
the 1970’s, it’s likely you used a text
book written by US electronics in¬
structor Bernard Grob. Two books that
come to mind are Basic Electronics and
Basic Television. I mentioned the latter
recently as a reference when discussing
baluns, which has drawn this letter
from a reader...
Having undertaken my TV Servicing
course before it even came to us in black
and white, I didn’t use the book by Ber¬
nard Grob, as mentioned in your
column. However, I think this author
might have been wrongly named by a
cruel quirk of fate. I suggest the author’s
name is Gross, not Grob, because of the
German use offi (beta) as a replacement
for l SS’. If so, we perhaps owe the
author an apology. (Sydney Clark,
Alexandria Hills, Qld.)
You could well be right Sydney, al¬
though there’s no reference to Gross in
either of the Grob books I have. Still,
quite a lot of Germans living in the US
found it socially prudent to anglicise
their name, particularly during both
world wars. For instance, 1920s pianist
Milton Suskind became Edgar Fairchild.
Lateral thinking
When I used this subheading before, it
was in reference to a question (March
’95) which asked for the next number in
the sequence 1, 4, 7, 11. The answer was
14, and the lateral bit was because the
number series was based on the use of
characters made from straight lines. But
there’s another lateral way to view the
question, as sent in by a reader. I’m sure
you’ll find it interesting and perhaps
grist for another party piece.
When I was first presented with the
puzzle 1,4, 7, 11..., I prided myself in
coming up with the answer of 15 in
under 10 minutes. However, as we
all know the answer is 14. My
lateral thinking solution to this question
goes like this:
The numeral 1 is written as 'one’,
having three letters. The next number is
4 (four), which has four letters. Then
comes 7, with five letters and 11, which
has six letters. So the next number must
have seven letters, and the lowest num¬
ber that fits this is 15. Oh well! (John
Lew, Hurstville NSW.)
There’s no right and wrong here. My
solution is one way to view the question
and to derive an answer. John’s is
another that is equally valid. In fact, I
suppose there are hundreds of possible
solutions. It’s just unfortunate that the
question and the answer have no use
other than to demonstrate lateral think¬
ing! But, as any serviceman knows,
lateral thinking is often a useful fault-
84
ELECTRONICS Australia, June 1995
finding technique, particularly when
you’ve exhausted all other avenues. The
lady who once insisted the cause for no
sound was the picture tube might just be
right. She could see the mouths move!
John has more to say on technical
subjects later in this column, but for
now we delve into a matter that
although not really electronic, is certain¬
ly about electricity.
Capturing lightning
You might recall a letter from a reader
(Patrick Mccool) seeking information
about a suitable capacitor for storing
lightning. I threw the question open to
readers, and in March ’95 I included a
letter from Malcolm Watts (NZ) who had
quite a bit to say on the dangers of
lightning. But since then, despite
Malcolm’s and my warnings, Patrick has
carried out some experiments, as ex¬
plained in this letter...
First, thanks to Malcolm Watts for his
concern and advice to readers telling
them DON'T DO U! However, we have
now successfully captured a fraction of a
lightning strike several times and are
still doing it from time to time. We have
readings of current and voltage as
measured by a Fluke multimeter.
We understand Mr Watts point of view
about high voltage from lightning, and
we are well aware that we are dealing
with a very dangerous activity. We apply
good and accurate planning, lots of care
and of course use correct wiring and
rewiring, based on lots of tests. If you
want to do something, you have to be
practical and cunning at all times, espe¬
cially if you are dealing with a high and
wild DC power source. So far the family,
pets and all are still alive and kicking!
Getting back to the main purpose of
this letter, we repeat that we are after up-
to-date information on where to buy or
get advice on how to assemble a suitable
storage capacitor. Our aim is to only
capture a small fraction of the power
from a lightning strike, storing it in a
small capacitor. Later we could increase
the size of the capacitor and perhaps
store more lightning. (Patrick and Julie
Mccool, Sanderson, NT.)
Unfortunately you haven’t given us
any details of how you went about this,
but full marks for, it seems, achieving
something very few readers would be
game to try — let alone succeed with.
I’ve included this letter, first as I’m sure
readers will be interested, and also to ask
readers for any information that might
help the Mccools in their experiments.
I wonder if a power factor capacitor as
used in electrical substations might suit.
These capacitors are physically large,
have a very high voltage rating, although
a relatively small capacitance, and can
be disassembled for repair. However,
I’m sure they are not readily available to
the public.
But Patrick, perhaps you could ask
your local electricity supply authority.
Even if they can’t directly help, per¬
haps they might be able to refer you
to a supplier. Another source might be a
radio station. High voltage capacitors are
used in radio (or TV) transmitters, al¬
though again I suspect the capacitance
will be too small. Still, you might be able
to get a number of them and connect
them in parallel.
The next letter is also from a Northern
Territory reader, who seeks information
about attracting lightning — not for
storage, but for other purposes.
/ was interested in your letter regard¬
ing lightning experiments from your
Darwin correspondent in December. I
live in Alice Springs and we also get
spectacular lightning displays from dry
storms during summer. One of my main
interests is photography, and I usually
set up my cameras on a suitable hill to
capture lightning on film. I have some
quite remarkable photos as a result.
I am interested in building a system to
attract lightning. This idea comes from
the US, where scientists launch a small
rocket trailing a fine wire aloft until it in¬
duces a lightning strike. This principle
would be handy to set up a lightning
strike in the subject area of a photo, and
possibly it could also be used to take a
measure of the lightning by attaching the
end of the wire to a suitable capacitor
and measuring apparatus.
The main problems would be a remote
control for rocket ignition, a suitable
rocket (possibly a model from a hobby
shop), determining the best time to
launch the rocket to achieve lightning ig¬
nition, and the distinct possibility that
repeated lightning strikes in my back¬
yard would disturb the neighbours! (Ian
Ross, Alice Springs, NT.)
The remote control system could be a
single-channel UHF unit, but I’m not
sure about the availability of a suitable
rocket. I seem to recall there are over¬
seas magazines devoted to the hobby of
rockets, so it shouldn’t be too difficult to
get something. However, if I was your
neighbour, I’d be rather alarmed at this
activity, so perhaps you might need to
fire the rocket over an uninhabited area.
You’ll get better scenery, anyway.
Magnetics
In case you’re starting to wonder when
the subject matter will become technical,
try this letter. It comes from a regular
correspondent to this column who often
takes me to task.
I see you are being provocative again,
in asking for a single answer for a
What?? question that is incompletely
specified. The March question about the
transformer with two resistors in circuit
is the case in point. The electrical part is
adequate, but the magnetic conditions
are not.
For a correct answer it is vital to know
how much of any increase or
decrease of flux in the core cuts the
various parts of the secondary winding.
Neither the question nor its explanatory
diagram (Fig.3) gives any clue about
this. Consider three (of a wide number)
of possible cases:
1. A pot core where flux changes are even¬
ly received by each element of length of
the winding.
2. A toroidal core (or its *square
equivalent with at least one cylindrical
leg to conform with Fig.3), and with the 1
ohm resistor andlor its half-winding in the
window.
3. As for 2 but with the resistors inter¬
changed.
My analysis of each is:
For case 1, each half of the winding
obtains equal exposure to changing flux
and there is a voltage of 3/2 = I .5V in¬
duced in each of the half turns A-B and
B-A. In the one ohm half, this is reduced
by the IV drop caused by the current of
I A, so the A-B voltage is 0.5. For the
other half, the 1.5V is reduced by the
current in the two ohm resistor to 2V.
This voltage leads the B-A voltage, so
the A-B voltage is 0.5V.
For case 2 all flux changes cut the
half-turn ‘ inside ’ the window, inducing
3V in it. The outside half sees no flux and
no induced voltage. In effect the inner
half has an internal impedance of one
ohm, decreasing its effect at the ter¬
minals by IV. That is, 2V is seen between
the terminals, exactly what is needed to
drive the lA through the two ohm resis¬
tor in the outer half.
For case 3, the same treatment as 2,
but with the two ohm resistor inside,
leading to IV between the terminals. By
the way, re the definition of ‘ inside f the
ELECTRONICS Australia, June 1995
85
INFORMATION CENTRE
core-space: anywhere in the winding
space that a wire can he cut by a line
of force as it collapses to zero
diameter when flux is reduced. (1 men¬
tion this because some people have
problems handling this concept). There
are other treatments of magnetics, but
this works for me. (E. Gordon Wor-
mald, Florey, ACT.)
Thanks for this, Gordon. Obviously
the question needed more detail, perhaps
to define the exact type of transformer.
Still, yours is the only letter I’ve
received, so possibly other readers didn’t
get so involved and saw the transformer
as a conventional device, not a pot core
type. I’ll try and be more careful next
time; at least that’s my story.
VCR mods for Philips TVs
In March a reader (B.F. Cooper, Tur-
ramurra) wrote asking if anyone could
supply the modifications so his TV set
could work properly with a VCR. The
receivers in question are Philips KD655
and Philips KJ239. Several readers have
sent me the necessary information, start¬
ing with the following:
After reading your March issue, /
noted you needed some VCR modifica¬
tion information. After digging around, /
located all the mods 1 have on Philips TV
sets. My information is based on chassis
numbers only, so I have matched these
models to a chassis. For the KD655
(K9A-2 chassis), use the K9A modifica¬
tion. For the KJ239 set, which has a
KT3A-1 chassis, use the KT3A modifica¬
tions: (Brad Hawkins, Taree, NSW.)
Here’s the information sent to me by
Brad, who from his letterhead, runs a TV
servicing business.
For Philips KT3A, KL9A, this altera¬
tion is used to improve frame
synchronisation when the set is used with
a National NV7000A VCR.
Step 1. Ensure the sync module (U475)
has a TDA257IAQ 1C (this applies for all
types of VCRs).
Step 2. Copper side: (a) increase the value
of C522 to 690uF by adding a 470uf 16V
electrolytic capacitor in parallel. (Later
models have a JOOOuF capacitor); (b) cut
the PCB track at pin 3 of U475; (c) con¬
nect a 220k resistor between C541 and the
base of Q514 (ie, pin 3 ofU475 is now no
longer connected.)
Step 3. U475 sync module: (a) ensure
R375 is fitted. If not, fit a 470 ohm resistor
in series with C374 (to pin 15 of IC367);
(b) reset the frame free running frequency;
(c) check the frame linearity, and adjust if
necessary; (d) remove R399 (180 ohm).
Philips KT3A chassis, line control
module U475 switch to VCR, final chan¬
nel position or line control module
U475. Connect pin 19 to junction of
R381 (27 ohm) and C386 (47uF) and
R393 (3.3k) (12V DC). For Philips K9A,
K11A chassis, models using line control
module U330, join pins 11 and 8, and
join pins 10 and 3.
Next is more information from R.
Percy, (Pambula Beach, NSW) who is
also a serviceman:
For the KD655 (which is a K9A-2
chassis), join pins 11 and 8 and join
pins 10 and 3 (as already described).
For the KJ239 (KT3A-1 chassis), this
chassis does not normally require
modification to work with a VCR if you
tune the VCR to the last tuning position
(normally 0 or U).
However if you want to use another
tuning position, do the modifications al¬
ready described for this chassis.
And finally, a reader (who I assume is
not a serviceman) has supplied this in¬
formation about the Philips K9.
I have a Philips K9 TV receiver, 1975
model and modification instructions
from Philips. The modification is to the
small signal panel. R4 is a four-pin sock¬
et and you need to connect pin 1 to pin 3,
and pin 2 to pin 4. (Len Rozife, Hast¬
ings, Vic.)
Thank you for this information, Len.
Yes, the last modifications seem to be
different to the first two, but I can only
present the information in the hope that
those stuck with trying to do it can work
out which set of instructions applies. I
assume there’s a difference between a
K9 chassis and a K9A chassis. Good
luck!
Electric field meter
In March I included information on
where to get a milligauss meter, to
measure the electromagnetic field
produced by a power line. At the time,
I did not know where to get an instru¬
ment capable of measuring the electric
field as well.
A supplier of these meters has since
contacted me: RFI Industries, of 54 Hol¬
loway Drive, Bayswater, 3153; phone
(03) 762 6733, fax (03) 762 8501. This
company also sells milligauss meters.
To give you an idea of what an
ELF/VLF electric field meter is, here’s
an extract from a promotional brochure
describing the Holoday HI-3638:
ELF range, 2Hz to 2kHz; VLF range,
2kHz to 400kHz. Dynamic range
0.4V/m to 40kV/m. The digital remote
readout included with the meter is iso¬
lated from the sensor with a two metre
fibre- optic cable. Using optional ex¬
tended cable lengths, the meter can be
separated from the readout by up to
300 metres. The instrument is battery
powered (NiCad) and can operate for
40 hours. The sensor has a diameter of
305mm and weighs lkg. The sensor
(looks like a satellite dish) fits on a
tripod and connects via the fibre-optic
link to the meter. The sensor can also
be connected directly to a computer.
The instrument is used in low field
measurements (eg, from a computer
monitor) to higher field environments
like those near power transmission lines.
I have no details on price.
Saba TV remote
Remember Saba TV sets? The follow¬
ing is from a reader seeking information
about the remote control system used by
these receivers.
1 am a hobbyist, and have been given
three small, reversible 25V AC electric
motors. They feature built-in gearing
and a clutch and were part of the remote
control system of an old Saba TV set. Ap¬
parently the remote control system works
at a certain frequency. 1 am after infor¬
mation about the system and in par¬
ticular the power supply circuit. If
anyone can help, Til be glad to reim¬
burse any costs. (M. Wolff, PO Box 116,
Surfers Paradise 4217.)
As far as I remember, the Saba system,
like others at the time, used an ultrasonic
remote control system, but with different
frequencies for each function. The
motors are used to drive the channel
changer, volume control and probably
the brightness control. If anyone can
help, perhaps you could contact Mr
Wolff at the address given.
Twin coax impedance
Here’s a question for all you transmis¬
sion line buffs:
At my last place of employment, a
computer system costing around
$600,000 was installed. The data in the
86
ELECTRONICS Australia, June 1995
system is transmitted to and from the
various terminals using two runs of 75
ohm coax.
Apparently to make installation easier,
the cables were joined together by their
sheaths as shown (see Fig.l). My ques¬
tion is, if the cable was used as a
balanced transmission line, what is its
characteristic impedance? (David Allen,
Findon, SA.)
When we discussed this in the office,
we decided that it was almost impossible
to say, as the coupling between the lines
caused by the shield would create so
many unknowns. But transmission lines,
like antennas (and baluns!) follow a dif¬
ferent set of rules to most branches of
electronics, and often defy rational
analysis. It would be interesting to
measure it.
Kits and projects
We pick up here the rest of John Lew’s
letter, which has a few comments about
tuner kits and an idea for a project:
Whatever happened to tuner kits? / for
one would love to construct one for my
hifi. Amplifier and speaker kits are con¬
stantly described and sold, but no tuner
kits. Are those who want to build as
much of their hifi system as possible a
dying breed? Or has the cost of commer¬
cial items made you conclude that a
tuner kit wouldn't sell?
I would also like to offer a project
idea. I want to build or modify a clock
radio so it only goes off on certain days
of the week (like Monday to Friday), ac¬
cording to the settings of switches. / ap¬
preciate my weekend sleep-in. (John
Lew, Hurstville NSW.)
The most recent tuner we have
described is the Playmaster AM/FM
Tuner, presented over a number of issues
in 1986. Others include the Playmaster
Stereo AM/FM Tuner (December 1985)
and the Playmaster HiFi AM Tuner over
various issues on 1983. Since then, I
must agree, we have not presented any
further tuner projects.
Our reasoning for not presenting
more tuner type projects is along the
lines you suggest, John, as commercial
tuners are now very refined, yet cheap.
However, the performance of the
Playmaster AM/FM Tuner is quite re¬
spectable, and it might still be available
as a kit.
As for the clock radio project, this
seems an excellent idea and one we
might look into. Again cost could be a
limiting factor, but the novel feature you
suggest could make it worth-
while.Thanks for the suggestion.
What??
This question comes from Jim Lowe,
who originally presented it as a ques¬
tion for TAFE NSW electrical teachers
and students.
In the circuit of Fig.2, each neon lamp
needs a minimum of 74V to ionise, so
four in series require 296V. After firing,
the voltage drop across each lamp is
59V. Because the supply voltage to the
circuit is 266V, the lamps don’t light
when the switch is closed.
However, what happens if a DVM
(with a resistance of 10M ohms) is con¬
nected as shown, and the switch is
closed? What will the meter read, and
what will happen when the meter is
taken out of the circuit?
Answer to
May’s What??
The average speed is 30kph. Let’s
assume each hill is 20km high. At
20kph, it takes the car one hour to
reach the top, and at 60kph it takes 20
minutes to descend.
The total time to travel 40km is there¬
fore 80 minutes, giving an average speed
of 40/1.3333 = 30kph. Averaging the two
speeds doesn’t give the right answer! ❖
PARTS LIST
Resistors
All 1/4W, 5% unless otherwise stated:
R1 3.3k
R2,3 22 ohm
R4 100 ohm, 5W
R5 220k
R6 270k
R7 6.8k
Capacitors
Cl ,4 0.47uF monolithic
C2 4.7nF polyester
C3 68nF ceramic
C5 220 to IOOOuF electrolytic
C6 22nF to 470nF 250V AC rated
Semiconductors
D1,2 BA159 or PLQ1 power switching diodes
D3-6 BA159 or MR856 power switching diodes
IC1 SG3525 switching 1C
Q1,2 P222 or MPT50N05E MOSFETs
Miscellaneous
PCB 125mm x 40mm; transformer to suit; optional
heatsinks; optional 16-pin 1C socket; hook up wire.
A Idt of parts for this project Is available from:
Oatley Electronics
5 Lansdowne Parade,
Oatley West, NSW 2223.
Phone (02) 579 4985
Postal address (mail orders):
PO Box 89, Oatley West NSW 2223.
Inverter kit, PCB and all on-board components in¬
cluding transformer and P222 MOSFETs $24.00
Inverter kit and 7,11 or
15W CFL to suit $36.00
Inverter kit and 20W electronic ballast $36.00
Inverter kit & 36W dimmable electronic
ballast $40.00
Post and pack charges $5.00
LAMP INVERTER
Continued from page 63
tion on CFLs for details of the different
types of CFLs.)
Otherwise, carefully check your con¬
struction. If all is well, it’s now a matter
of deciding what to do with the in¬
verter. There are plenty of options, as
we’ll now describe.
Applications
As we’ve already explained, there are
three main options: using the inverter
with one or more CFLs, with a 20W
electronic ballast and fluorescent tube,
or with a 36W dimmable electronic bal¬
last and tube. The DC supply to the in¬
verter can range from 10V to 15V.
The obvious application is internal
lighting from a solar-powered 12V bat¬
tery charging system. This could in¬
clude boats, caravans, camp sites and of
course, a residence. Because the one in¬
verter can drive several lamps, you
could even use conventional house
wiring to connect the lamps.
This way, a conventional light switch
can be used to operate a light driven
from the inverter. While a typical light
switch is only rated for AC, the current
taken by a 20W lamp at 350V DC is
less than 60mA, which should be well
within the rating of a 10A AC rated
switch. Because the inverter draws a
no-load current, some arrangement is
needed with a multi-lamp system to iso¬
late the inverter from the 12V supply
when all lamps are off.
Another application is a low voltage
garden lighting system. With this arran¬
gement, run a 12V supply to each lamp
fitting, and install an inverter in each
one. A low cost fitting made from a
large Nescafe coffee jar and PVC
plumbing is shown in Fig.7. This Fitting
was made with 90mm SWV pipe, which
is readily available from most hardware
shops. The jar was joined to the pipe with
a 90mm joiner, and the total material cost
was around $4.
The wiring to the fittings has to have a
low resistance, to keep the voltage drop
as low as possible. However, the light
output of a CFL is virtually constant for
an input voltage to the inverter down to
about 10V. Remember too that the
electronic ballasts referred to in this ar¬
ticle can also be powered directly from
240V AC. So there’s really quite a few
options available. ❖
ELECTRONICS Australia, June 1995
87
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ventila-
to allow for
adequate air flow • Molded bosses/^^^^^^^^^^
or stand-offs to accommodate PCB's direct onto the base of the box
• Integral brass inserts to accept the front panel holding screws
• Stylish brushed natural aluminium face plate • Supplied with
stick on rubber feet and self tapping screws for securing PCB's
H 0436 170 143 31 55 JlD Accuracy:.
£ 00.95 V\TS<; Display:.
H0438 170 213 31 82 $22 ° 00 Q 1010 $199 °°
Multi-Function Remote Car Alarm
This amazing model features just about everything you could imagine. Multi-function key
ring remote control will arm and disarm alarm (and activate central locking if fitted), —
panic and even open the boot (if actuator fitted). Other fea- yv
tures include starter inhibitor, valet mode, central lockin g
interface, flashes car indicators when tripped, auto : r
reset, user programmable options plus much more.
Also includes two spare electric outputs which are
operated by the key ring remote control, these can be 4 „
used to chirp the horn, turn on the car headlights or a myriad
of other functions! Can be configured to automatically re-arm if a ^
door is not opened within 22 seconds after disarming (avoids accidental disarming).
Full battery backup siren includes built-in batteries, charging circuit, siren and key
on/off switch.
Features: • Supplied complete with two miniature remote controls • Remote arming apta
and disarming • Super Loud 127dB siren • Remote panic function • Full battery
backup and tamper proof siren • Child proofing and anti intrusion alert while dri-
, "y the Best LCR
Meter We Have I
Ever Evaluated! |
360° Ceiling Mount
Passive Infra-Red
Movement Detector
Incorporates Pulse Count Triggering
With an attractive slimline design, this ceiling
mounted detector offers a great degree of pro¬
tection. Ideal for offices, factories, shopping
centres etc with wide expanses, where the walls
are too far apart for conventional wall mounted
movement detectors. This
unit is also ideal for
home systems to pro- ¥
tect individual rooms.
Covers area approx 4 L
x 11m at 110°. #
Central Door Locking Kit
All four doors will automatically -
lock or unlock with the operation ^
of either of the front doors.
Add the ease and convenience of central
locking to your car. Can be interfaced to
our S 5205 car alarm (and others) to lock
or unlock all four doors when the alarm '
is remotely armed or disarmed.
Includes all the mounting hardware to
fit to most cars. The actuators are
motorised with an inbuilt gearbox to
ensure reliable and positive operation.
One actuator is mounted inside each
door. Includes central control unit
which mounts under the car dash. For
use with 12V negative earth systems. -
S 5237 $119 °°
Famous Maestro Internal Fax/Modems
Fantastic Offer at Never to be Repeated Prices!!
Using the latest in digital signal processing these modems will give you years of service.
All models are supplied with Quicklink II Fax software and are backed with full support
by Maestro. Quicklink II offers some great features like sending faxes to several numbers
simultaneously, viewing incoming and outgoing faxes on-screen, receiving faxes in the
background while using other programs, scheduling faxes, and much more!
«n/, CarA,a ”"
,. ° Ck/U »lock
the Doors by
^!L£o*trol!
D 1610 Economy
Internal Fax 9600/Data 2.4.kbps
D 1620 Exec Internal up to
Fax / Data 14.4kbps Normally $549
This Month Only $299
Self Powered Electronic Piezo Siren with
Rechargeable Built-In Battery
Self contained unit. Incredibly loud siren out- ..
put of 120dB. Connects to 12V DC. If
either the trigger or power wires are
cut, the siren will sound. Will also |$ \ k J
sound if the car's battery is dis-con- ;! \ ™ ‘ 1
nected. Simply armed and disarmed I
via inbuilt key switch (2 keys sup- I -
Features: * 120dB output • Built in back
up battery • Compact design • Easily inter-
faces with house or car alarm • Easy key switch
operation
S 5235 Normally $69 95
This Month Only $39 WMgMMBm
Normally $249 00
This Month Only $159
Speaker Protect Grills for Your Mobile
Disco or Stage Sound Gear
Add some class to your speaker cabinets with this professional series of wire grills. Sturdy
steel construction features plastic surround and open grid appearance. Each includes 4 fix¬
ing clamps. Black only.
To Suit Each includes
Speaker Size 4 fixing clamps^g^KM
C 3706 6.5" (165mm) $8' 95
C 3708 8" (200mm) $10 93
C 3710 10" (250mm) $13*
C 3712 12" (300mm) $i6 ,s a
C 3715 15" (380mm)
Extra Large 22mm
Digit DMM 4
Includes Capacitance Ranges and
Temperature Meter.
Features:
• Capacitance measurement
(includes thermocouple)
• Resistance to 200M ohm • Diode I
after 15 minutes
range
Specifications:
DC Voltage Ranges:
200m V, 2V, 20V, 200V, 1000V
Input Impedance:.10MQ
AC Voltage Range:.2V, 20V, 200V, 7tX)V
Input Impedance:.10MQ
DC Current Ranges:...2mA, 20mA, 200mA, 20A
AC Current Ranges:.200mA, 20A
Resistance Ranges:.200Q, 2kQ, 20kQ, 200kQ,
2MD, 20MQ, 200MQ
Capacitance Ranges:2nF, 20nF, 200nF, 2pF, 20pF
s ysten JS !
Buy Both the S 5205
Car Alarm and the
S 5237 Central Locking
Kit for $279 and Save!
This External Siren
will Immediately Sound
if it's Wires are Cut.
Includes Internal
Rechargeable Batteries!
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DOC. JH183
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Vim com Electronics (042) 284400
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Standard Delivery & Packing Charge: $4.00 to 500gms, $5.50 500gms-l kg, $8.00 lkg-5kg.
Where possible we process your order the day received and despatch via Australia Post.
Allow approx 9 days from day you post order to when you receive goods.
Overnight Jetservice: Up to 3kg is $10.00, 3kg to 5kg is $18.00—We will process your order
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Altronics Resellers: Chances are there is an Altronics Reseller right near you—check this
list or phone us for details of the nearest dealer. Blue Ribbon Dealers are highlighted with a
#. These dealers generally carry a comprehensive range of Altronic products and kits or
will order any required item for you.
© Altronics 1995. All possible care has been taken with the preparation of this advert and
the information contained herein is correct at the time of going to press however specifica¬
tions and particulars in relation to products referred to herein are subject to change without
notice. Altronics takes no responsibility for any loss or damage howsoever caused suffered
by a reader with respect to any matter or thing referred to herein. Prices stated herein are
only valid for the current month or until stocks run out.
fit
amous Labtech 20MHz Dual Trace
Wireless Diversity Microphone Systems
These professional wireless microphone systems are as used by the industry for stage and
studio productions. Featuring stylish good looks and the latest microchip technology they
offer outstanding performance and sound reproduction both for voice and instrumental
applications. True Diversity Reception means two
receivers with separate antennae are employed. An
on-board microchip monitors the signal strength
and reception fidelity of either A or B receiver and
automatically outputs the highest quality signal.
Each system includes a receiver unit and a hand
held microphone. The receiver operates from
240V AC and simply connects to an amplifier
with a line level input. The microphone
requires a 9V battery (not supplied).
Two Frequencies Available:
System 1 - 202.5MHz
System 2 - 202.9MHz
Each System
Normally $744°°,
This Month Only $544
Complete System
The Powerhouse 1200W Inverter Kits
----” l(See EA Feb '92) This Power Inverter will provide all
Connects Direct to Your y^ f e I your power requirements from a heavy duty 12 or
Battery to Produce 240 V AC. 1 24 y battery. Using the latest Mosfet output stage and
toroidal transformer this inverter is both efficient
and will deliver high surge currents. The
Powerhouse has been designed not
only for rugged bullet proof opera¬
tion but for ease of construction,
two PCB's hold all circuitry with one
inter-connecting cable. This kit
comes to you in a fully drilled, pre
punched chassis complete with silk
screened front panel. Suitable for use in
camping, boating, fishing, mining, farming, remote settlements etc.
K 6796 Kit Version 12V Input <fc' 7 QQ.OO
K 6798 Kit Version 24V Input
K 6797 Fully Built & Tested 12V Input £qqq c
K 6799 Fully Built & Tested 24V Input
1GHz Frequency Counter
This multiple-function counter
covers a range of 10Hz to
1 GHz. It includes an eight
digit, seven segment, LED
display, low power consump¬
tion circuit design, small size,
light weight, highly sta¬
bilised crystal oscillator
for accurate measure¬
ment and full input
signal conditioning.
Q1535
Normally $399 00
This Month Only $299
Genuine Austel Approved
Telephone Line Isolation
Transformers
These PCB mounted transformers are used by manufac¬
turers throughout Australia. They feature an impedance
of 600Q for the input and output
windings. Full specifications are
available upon request.
M 1000 Normally $13 95
This Month Only $6 ea
Or Buy 10 and up $5 ea
Oscilloscope
This model is a
dual trace,
20MHz oscillo¬
scope with a
high brightness
CRT. Theverti- |
cal amplifiers
have high sen¬
sitivity of
5mV/div and a
frequency characteristic
response with a smooth roll
off exceeding 20MHz. The
TV sync, signal operator cir¬
cuit is provided to ensure sta¬
ble observation of video signals. Triggering
is obtained by sampling the AC power wave¬
form, external waveform or internally generat¬
ed trigger.
$729.00
Q 0156 Normally C
This Month Only
$649
Q 0175 Cro Probes to Suit $49 , 5 E3ch
Now With Component
Test Function!
Now Over 2000 i tl scrvic
throughout Australia
"•eluding many WO s in
Universities, Research
Establishments and
Q 0175
Cro Probe
Doc.JH183
Experimenting
with Electronics ,
Putting transistors to use
If you’re looking to start designing your own circuits and building your own projects, then you won’t
come across a component more versatile than the transistor. Over the next couple of months, we’ll
look at some of the many ways you can use a transistor to great effect.
There is an attitude in society which
seems to suggest that we make things
simpler by making them more compli¬
cated. You only have to look at the num¬
ber of microprocessor-controlled widgets
and whizzbangs floating around — wash¬
ing machines, videos —just about every¬
thing you can buy.
Now while they obviously allow more
people to use the products, anyone who
wants to service their own widget is in
for one heck of a nightmare.
As far as active electronic components
are concerned, the transistor would be the
most useful and simplest to use. In es¬
sence, it’s operation is fairly simple — a
small current is applied to the base to
control a much larger current flow be¬
tween the emitter and collector. It’s this
amplification capability of the transistor
that makes it so useful. However, there
are many other things you can do with it
besides making a simple amplifier, as we
shall see over the next couple of months.
A simple amplifier
If you’ve never seen one before, then
here it is in Fig.l — the world’s simplest
audio amplifier. It’s a ‘common emitter’
design, so called because the emitter is
the common connection between the
input and output signals. This circuit uses
a current bias at its base, supplied by the
1MQ resistor. It also provides the nega¬
tive feedback for the circuit too. Let’s see
how this works.
When power is first applied, Q1 is sud¬
denly turned on by the current flow
through the 4.7kf2 collector resistor and
the lMf2 bias resistor. As the transistor
turns on, the collector voltage decreases.
This reduces the amount of bias current
to the base, which forces the transistor to
begin turning off. As it turns off, the col¬
lector voltage rises. More current flows to
the base and Q1 turns on again.
This apparent swaying between one
state and the other all happens quite
rapidly and with the components and
supply voltage specified, the collector
voltage quickly reaches half the supply
rail, the ideal spot for the output of an
audio amplifier.
The two 0.1 uF capacitors isolate the
input and output from the DC voltages, to
ensure that the DC bias points are not
upset by outside loads.
The input impedance is only fairly low,
due to the fact that there is no emitter
resistor in this circuit. The AC input im¬
pedance of the circuit is roughly equal to
the beta (current gain, or amplification
factor) of the transistor, times the internal
emitter resistance of the transistor.
This last factor is often known as ‘little
r-e’ and in our circuit, it is around 25
ohms, multiply that by 100 as a minimum
figure for the gain of a BC547 transistor
and you get an overall input impedance
of around 2.5kQ.
The output impedance is much easier
to work out. As a rough guide, it is simp¬
ly the value you have for the collector
resistor — in this case, 4.7kQ.
Now while you can’t connect a
loudspeaker to the output and expect to
hear an awful lot, you can easily use it as
a cheap microphone preamplifier. It will
provide a gain of around 200, which is
more than enough to drive your stereo
system to a suitable level. Connect up a
dynamic microphone to the input and
the output to the line input of your
stereo, and you’ve got a simple karaoke
mic system.
Better control
The old saying is ‘whatever can be
done with one, can be often done better
with two’, and this is very true when it
comes to transistor amplifiers. The circuit
in Fig.2 is an equally common circuit and
included for completeness; however it
does have a number of advantages over
the circuit in Fig. 1.
Firstly, it has a much higher sound
quality. In more technical terms, it has a
lower amount of total harmonic distortion
(THD). Simply, this is the amount of
extra nasties the amplifier itself adds to
the output signal. While you can’t get rid
of it completely, you can reduce it down
to inaudible levels.
The new circuit has a much more
stable method of applying negative feed¬
back. In this case, the feedback is taken
from the output (as before) via a 2.2kQ
resistor from the collector of transistor
Q2, and fed to the emitter of Ql. Now
while it may not be obvious, the emitter
of Ql is actually another input point. A
signal applied to the emitter of a tran¬
sistor will appear in the same phase at
the collector.
The 100Q resistor R1 and the lOuF
capacitor, along with the 2.2kQ feedback
resistor R2 form a voltage divider for the
feedback, which is extremely stable. By
stable, I mean that it is not varied by the
characteristics of the transistors used.
In Fig.l, the feedback, and hence the
overall gain which we’ll get to shortly, is
controlled by the beta of the transistor.
The problem here is that transistor betas
can vary over a range of 4 to 1 and more.
Some types of BC547’s will have a beta
ELECTRONICS Australia, June 1995
91
EXPERIMENTING
of 100 and others as high as 400. This
type of variation ensures that the gain of
Fig. 1 ’s circuit will always vary.
By contrast, the gain of Fig.2’s circuit
is simply 1+(R2/R1), or
l+(2200/100)=23 as in the case of our
circuit. To increase the gain, you reduce
the negative feedback and vice versa.
This is done by reducing or increasing,
the 100ft resistor. If you change the
2.2kft resistor, you will upset the DC
bias points; so always stick with the same
value of R2.
Strictly speaking the 33kft collector
resistor on Q1 is not necessary, but it
greatly reduces the amount of distortion
— by a factor of five or more. It helps to
linearise the current flow through the
base of Q2.
The output voltage, at the collector of
Q2, is set to 4.5V with a 9V supply rail
and is set by the 100k and 150kft resis¬
tors biasing Ql. The base bias voltage of
Q1 sits about 0.6V above half the supply
rail, to allow for the 0.6V drop across the
transistor’s base-emitter junction. You
can vary the supply voltage over a range
of 6-18VDC and the output will be pretty
close to half the supply rail. This ensures
that the circuit can deliver the maximum
voltage swing with little distortion.
Another factor which adds to THD is
hum, or 50Hz leakage from your power
supply into the audio path. If you’re
running from batteries, this is generally
not a problem; but if you’re running the
circuit from a plug pack, you’ll find quite
a bit of hum getting through via the supp¬
ly rails.
The lOkft resistor and lOuF capacitor
on the left together act as a very low-pass
filter, to remove the mains hum leakage
and ensure that the input bias voltage for
Ql is as stable as possible.
The output impedance here is again
determined largely by the collector resis¬
tor of Q2, and in this case, is ap¬
proximately 1 kft. The benefit of this cir¬
cuit though is that the output impedance
can be either reduced or increased
without greatly affecting the overall gain
of the circuit, since the collector resistor
is not part of the feedback network.
This circuit has a distortion figure of
around 0.1%, but with higher supply vol¬
tages (i.e., around 18V or so) the distor¬
tion can drop as low as 0.05%.
More noise
While transistors can be used to
amplify other noises, they can also be
used to generate their own. The simple
circuit in Fig.3 is a square wave oscillator
which starts as soon as you apply the
supply voltage. It’s official name is a
‘cross-coupled astable multivibrator’ —
‘cross-coupled’ because the RC com¬
ponents connect the output of each tran¬
sistor to the input of the other, ‘astable’
because neither transistor has a stable
operating state, and ‘multivibrator’ be¬
cause it continues to oscillate indefinitely.
Both transistors are common BC547
types, which should cost you around 20c
each or less. While this circuit may look
fairly simple, it is more difficult than it
looks to figure out how it works.
The difficulty with the circuit lies in the
fact that there are really two parts to it,
and it is impossible to figure out which
part — that of Ql or that of Q2 — will
switch on first. In practice, all you need
to remember is that when one transistor is
on, the other is off; and when each tran¬
sistor is on, its output voltage is low,
while and when it is off, the output volt¬
age is high.
It’s not necessary to know which sec¬
tion switches on first — this ultimately
depends on which of the two O.luF
capacitors charges up first. Let’s assume
capacitor C2 is charged up before Cl.
What happens here is that at some point,
there is enough charge to turn on one of
the transistors; and because of the cross-
coupled arrangement, one transistor turns
on and the other is forced off.
C2 charging up first means that transis¬
tor Ql switches on and Q2 is forced off.
The reason for this is that when Ql
switches on, the Q2-base side of
capacitor Cl is pulled below 0V! Now
this may sound impossible, but it happens
because capacitors cannot instantly get
rid of or change the charge that is stored
inside. So if one side of the capacitor
drops from 5V down to 0V, the other side
must go from 0 to -5V.
This well and truly forces Q2 off; but
Cl now begins to charge up in the
reverse direction until it reaches 0.7V, the
limit forced upon it by the base-emitter
junction voltage of Q2. Transistor Q2
now switches on, and its collector voltage
drops from 5V down to 0V.
Capacitor C2 is now forced to go from
0.7V down to -4.3V (a 5V drop) which
forces Ql off. But C2 now also charges
back up, until it reaches 0.7V when Ql
switches back on. The process then con¬
tinues on, cycling back and forth until the
power is removed.
The frequency of this circuit is depend¬
ent upon the two RC networks, and
providing both the resistors (Rl, R2) and
both capacitors (Cl, C2) have the same
value, the frequency is determined rough¬
ly by the following equation:
F= l/(RxC)
where F is the frequency in Hz, R is the
resistance of Rl or R2 in ohms and C is
the capacitance of Cl or C2 in Farads.
The output is a square wave with both
sets of components having equal values.
The output signal is taken from the col¬
lector of transistor Q2 via a luF DC
isolating capacitor and a lOkft load resis¬
tor. The other interesting aspect of this
circuit is that and opposite-polarity signal
is available from the collector of transis¬
tor Ql, which can be very handy and
something that we’ll use in a future issue.
92
ELECTRONICS Australia, June 1995
If you remember back to
last month’s column, we came
up with a simple voltage-con-
trolled volume control using a
couple of series diodes. If we
remove the DC volume pot
and replace it with our newly
created square wave oscil¬
lator, we can make a very
crude ‘Robot Voice’ circuit as
shown in Fig.4.
The audio signal, either
from a tape source or from a
microphone preamplifier, is
fed into the circuit via a 0.1 uF
coupling capacitor. While the
collector of Q2 is low, both
diodes are off and the audio
signal passes through the cir¬
cuit as if nothing happened. But when the
collector voltage rises to 5V, both diodes
conduct and the audio signal is shunted to
ground and the output goes silent.
By switching the audio off and on like
this at 200 times a second, the effect is to
chop the sound up, and this chopping ac¬
tion produces a beat frequency in the
audio at 200Hz. It’s this beat frequency
which gives the audio that ‘robotic’
flavour. All you need to do is connect the
audio output to a small power amplifier
to hear the result.
There is plenty of room for ex¬
perimenting with this circuit, particularly
with the frequency of the oscillator. Try
dropping the 0.1 uF capacitors down to
0.047uF (47nF) and see what results you
get. What you should find is that the beat
frequency rises to around 400Hz.
This is a good example of how you can
join these little ‘building block’ circuits
together, to create something different. In
fact, that’s all electronics really is —
working out new arrangements for com¬
mon circuit elements.
Current source
Our last circuit for this month moves
away from the audio domain and into the
realms of voltage and current control.
The circuit in Fig.5 is commonly called a
constant current source , and that’s be¬
cause the current that flows through the
collector of Q1 is 60mA, regardless of
how small the load resistance is. Let’s see
how it works.
So far we’ve used the transistor as a
switch and as an amplifier, but here we
take advantage of the transistor’s base-
emitter junction voltage — which hovers
around 0.6V. Another difference in this
circuit is the use of a BC327 PNP transis¬
tor. It operates in essentially the same
fashion as the NPN type, just ‘upside
down’, as we’ll see.
Diodes D1 and D2 are standard
1N914/1N4148 types wired in series,
with a 330Q current-limiting resistor
connected to ground. Because silicon
diodes develop a fixed 0.6V drop across
them, we know that the voltage at the
junction of D2 and the 330Q resistor will
be 7.8V (i.e., 9V minus twice 0.6V). This
junction is also connected to the base of
the PNP transistor Ql, and now the
transistor’s base-emitter junction comes
into play.
Because we know that the B-E junction
voltage is always 0.6V, the emitter of Ql
is 0.6V higher than its base. And as the
base is at 7.8V, this makes the emitter
voltage 8.4V. We therefore have 0.6V
across the 10Q emitter resistor.
With most small signal transistors, you
can take it as a good rule of thumb that
the collector current is equal to the emit¬
ter current.
Now while this depends on factors
such as the base current flow and the gain
of the transistor, these factors play on a
tiny part in high gain transistors such as
the BC5XX and BC3XX types.
Since we have a fixed resistance and
voltage determining the transistor’s emit¬
ter current, we therefore have a fixed
current flow through the collector as
well, regardless of how small the collec¬
tor load is. In practice, there is
a limit to how low you can go,
with the load resistance be¬
tween collector and ground.
But this is more to do with the
power dissipated by the tran¬
sistor than the excessive cur¬
rent flow. With the transistor
turned fully on, we can as¬
sume that there is no voltage
drop between the emitter and
collector and that we have a
maximum voltage of 8.4V at
the collector.
Now of course we can put a
\k£l resistor between the col¬
lector and ground and the cur¬
rent flow will only be
8.4V/1000 or 8.4mA. But the
circuit is designed to feed a constant cur¬
rent into a low impedance, which it does
very well.
This is pretty much the only thing you
need to consider when using constant
current sources in basic circuits — don’t
load them up with too high an impedance
or you’ll drop too much voltage across
the load, and the transistor won’t be able
to control the current.
An example of where this circuit can
be used is as a simple NiCad battery
charger. NiCad cells are best recharged
using a constant current source. In fact,
you could easily connect your 1.2V ‘AA’,
‘C’ or ‘D’ size cell between the collector
and ground and it will eventually charge
up. In fact, there have been quite a few
projects in Electronics Australia that have
used a circuit such as this, as the basis of
a full blown multi-cell charger.
You can easily modify this circuit, par¬
ticularly the amount of current the circuit
can provide, by working out the follow¬
ing equation:
lout = 0.6V/Rx
where lout is the constant current in
amps and Rx is the value of the emitter
resistor. If we change Rx to 56 ohms, the
current drops back to just over 10mA and
we can now easily and safely charge up
7.2V transistor batteries. The only thing
you need to worry about with a circuit as
simple as this is that you don’t over¬
charge the batteries.
A fair proportion of circuits using this
approach also incorporate a timer, which
automatically switches off the circuit
after 15 or so hours. We will pick up this
idea in a later issue.
Well, that’s enough for this month.
Next month, we’ll continue with our look
at transistor circuits with some common
and some not so common designs.
{Darren Yates is Chief Engineering Of¬
ficer with R.A.T. Electronics, of P.O. Box
641, Penrith 2750.)*
ELECTRONICS Australia, June 1995
93
NOTES AND ERRATA
Playmaster 300W subwoofer amp
(April 1995): The amp module’s
schematic on page 61 shows D4 con¬
nected the wrong way around — it’s
anode should face Cl6. The PCB over¬
lay in the May issue is correct.
Experimenting with Electronics —
Sounds on board (April 1995): Due to
an unfortunate glitch in our production
system, all of the parts lists were
omitted, along with the information on
kit availability. We apologise for this
error, and the missing information is
shown below.
Digital Trigger Adapter for Scopes
(April 1995): The PCB overlay diagrams
on page 85 were printed incorrectly, with
the component outline information not
reproduced at all. The diagrams on the
right show (hopefully!) the overlays as
they should have been printed. Our
apologies for this problem, even though
not of our making.
Roulette Wheel (April 1995): The PCB
overlay diagram on page 50 was again
printed incorrectly, with the component
outline information missing. As before,
the diagram is hopefully reproduced cor¬
rectly on the facing page.
EA’s Reader Information Service
BBS: We have now installed a new
Dynalink 1428VQE high speed modem,
able to operate at speeds up to 19,200b/s.
PARTS LIST
Train sounds (SGI)
Resistors
All 1/4W, 5%
R1 150k
I R2 330 ohm
Capacitors
Cl O.luFmono
Semiconductors
Q1 BC547 NPN transistor
COB train sound generator SGI
Miscellaneous
four x N/O pushbuttons; 8 ohm speaker;
strip board or equivalent to accept COB
PCB and components.
16-tunes (SG3)
Resistors
All 1/4W, 5%
R1 390k
Capacitors
Cl ,2 10uF 16V electrolytic
C3 O.luFmono
Semiconductors
Q1 BC547 NPN transistor
COB 16-tune sound generator SG3
LED1 . 5mm LED
Miscellaneous
one N/O pushbutton; 8 ohm speaker; strip
board or equivalent to accept COB PCB
and components.
Ding-dong sound (SG5)
Resistors
All 1/4W, 5%
R1 470k
R2 150k
R3 1M
R4 330k
Semiconductors
Q1 BC557 PNP transistor
Q2 BC547 NPN transistor
COB ding-dong sound
generator (SG5)
Miscellaneous
one N/O pushbutton; 8 ohm speaker; strip
board or equivalent to accept COB PCB
and components.
Phone sounds (SG2)
Resistors
All 1/4W, 5%
R1 100 ohm
R2 330k
Semiconductors
Q1 BC547 NPN transistor
COB phone sounds generator SG2
Miscellaneous
eight x N/O pushbuttons; 8 ohm speaker;
strip board or equivalent to accept COB
PCB and components.
Gun and siren sounds (SG4)
Resistors
All 1/4W, 5%
R1 330k
Semiconductors
Q1 BC547 NPN transistor
COB gun and siren sound
generator SG4
LED1.2 5mm LED
Miscellaneous
N/O pushbuttons as required; 8 ohm
speaker; strip board or equivalent to accept
COB PCB and components.
Getting COBs and COB kits
Kits of parts for the COB projects
described in this article are available
from:
Alpine Technologies
PO Box 934,
Mt Waverley 3149.
Fax/phone (03) 751 1989.
Kits for SGI and SG2 cost $6.95; for SG3
and SG4, $6.25; and for SG5 $5, including
postage. Kits also include documentation,
speaker and battery holder, but no bat¬
teries.
Individual sound generator COBs are
also available from:
Oatley Electronics
5 Lansdowne Parade,
Oatley West, NSW 2223.
Phone (02) 579 4985
Postal address (mail orders):
PO Box 89, Oatley West NSW 2223.
The SGI and SG2 sound generator COBs
cost $3, while those for SG2, SG4 and SG5
cost $2.50.
94
ELECTRONICS Australia, June 1995
PC-Based DSO Adaptor Mk2 (May-
July 1994): David Jones, of Tronnort
Technology has suggested the following
modifications, to improve performance
of this project.
1. If triggering is unstable in START
mode, try adding a bypass capacitor of
100 - 220pF across R28.
2. For improved triggering stability in
both START and STOP modes, replace
switch S6 with a DPDT type and wire
one pole as shown in the original
schematic. Then remove the under¬
board link between pin 15 of J2 wire and
pin 8 of U9b, and connect it instead be¬
tween pin 15 of J2 and the second pole
of S6. Now wire pin 8 of U9b to the
STOP side of S6b, and connect pin 1 of
U 10a to the START side of S6b.
3. To eliminate any nonlinearity near
full scale vertical delection, replace R35
with a wire link. This prevents R35 from
disturbing the gain of U8b, at higher out¬
put levels.
4. To prevent erratic address in¬
crementing by the computer, especially
in STOP mode, bypass pin 13 of U lOd to
ground with a 47pF capacitor.
David Jones has also produced a new
version of his DSOA software, Version
3.3a. From V3.2 an upgrade costs $10,
or from earlier versions $15 — including
packing and postage. Send orders to
Tronnort Technology, 12 Copeland
Road, Lethbridge Park 2770.
Automotive Electronics (April 1995):
On page 94 the ‘No.l ignition trig¬
gering probe’ is described as cou¬
pling to spark plug leads capacitively.
In fact, these probes employ inductive
coupling.
Inside the probe is about ten turns of
fine copper wire wound around a fer¬
rite^’ core, which mates with a ferrite
T’ core inside the hinged part of the
probe. When the probe is clamped over
a high voltage lead, the probe thus acts
as a current transformer.
ROCKAV
OVERSTOCKED
CLEARANCE SALE!!!
EPROMS
27C256-12
$2.90
27C512-10
$3.50
271001-15
$4.50
REGULATORS
7805T
$0.31
LM317T
$0.50
INTERGRATED CIRCUITS
LM324N
$0.28
LM741N
$0.28
NE555
$0.28
MC14021CP
$0.20
MC146818P
$1.00
LM339N
$0.28
MONOLYTHIC CAPACITORS
O.luF 0.2"
$0,035
0.01uF(RT)
$0,025
O.luF (RT)
$0,025
TANTALUM CAPACITORS
15uF 25V
$0.20
33uF 10V
$0.18
33uF 16V
$0.28
22uF 16V
$0.26
4.7uF 16V
$0.19
OPTO COUPLES
4N32
$0.30
M0C8204
$0.30
RED/AMBER (DUAL COLOUR
5mm ROUND) LED
$0.25
TRANISTTORS
TIP3055
$0.90
PN2222
$0.04
MACHINED I.C. SOCKETS
8 PIN
$0.10
16 PIN
$0.20
28 PIN
$0.30
40 PIN
$0.40
DIODES
1N4148
$0,019
1N4004
$0.02
1N5402
$0.07
ALL STOCK IS SUBJECT TO 21% SALES TAX
STOCK IS SUBJECT TO PRIOR SALE.
For a full 200 page Trade or Retail Catalogue
please send $6.00 +$ 1.50 postage.
(Please Indicate whether you are trade or retail.)
R0CKBY ELECTRONICS PTY LTD.
261 Huntingdale Rd HUHTIN60ALE VIC. 3166
P.0 BOX 189 HUNTIN6DAIE VIC 3166
PH. 03 S62 8SS9 FAX. 03 $62 8772
ELECTRONICS Australia. June 1995
95
READER INFO NO. 20
Eprom & Sram Emulator
2K x 8 to 64K x 8. Download and verify
Program via standard PC printer port.
Supports Binary, Intel and Motorola hex
formats, including Binary Edit. More
information Contact Quick Link
Engineering P/L, 472 Glenhuntly Rd
Elsternwick Vic 3185 Ph: (03) 532 8775
(03) 532 8355.
New Sprinkler controller kits:
RAIN BRAIN version uses 'C8 and
switch mode supply. Features galore!!
Contact Mantis Micro Products, 38
Garnet ST. Niddrie, 3042 Phone/Fax
(03) 337 1917.
Tiny Video Cameras:
from $199 MATCHBOX SIZE PCB
MODULES from 32 x 32 x 15mm with
lens. 25 types. Optional lenses, C lens
mounts, cases & technical manuals. See
review pg138 EA Nov ‘94. Allthings
Ph/Fax (09) 349 9413.
Amidon Ferromagnetic Cores:
For all RF applications. Send business
size SASE for data/price to RJ&US
Imports, Box 431, Kiama NSW 2533.
Agencies at Geoff Wood Electronics,
Sydney; Webb Electronics, Albury;
Assoc TV Service, Hobart; Truscotts
Electronic World, Melbourne and
Mildura; Alpha Tango Products, Perth.
Network Software:
Little Big LAN uses Serial, Parallel,
Arcnet or Ethernet to share files and
printers on your PC’s. DOS and
Windows compatible. $105 per network.
All prices + postage. GRANTRONICS,
PO Box 275, Wentworthville. 2145.
Ph/Fax (02) 631 1236.
“The homebuilt dynamo”:
(construction plans), brushless electric
generator, 1000 watt DC at 740 RPM.
A$85 postpaid airmail from Al Forbes,
Box 3919-EA, Auckland, New Zealand,
phone 0011 649 818 8967 anytime.
Philips Ferroxdure rotor magnets (3700
gauss) kit now available cut to size and
magnetised. Fax: 64 9 818 8890.
96 ELECTRONICS Australia, June 1995
C Compilers:
Everything you need to develop C and
ASM software for 68HC08, 6809,
68HC11,68HC16, 8051/52, 8080/85,
8086 or 8096: $150.00 each. Macro
Cross Assemblers for these CPUs +
6800/01/03/05 and 6502: $150 for the
set. Debug monitors: $75 for the 6
CPU’s. All compilers, XASMs and
monitors: $450. 8051/52 or 80C320
Simulator (fast): $75. Demo disk: $5. All
prices + postage. GRANTRONICS, PO
Box 275, Wentworthville. 2145. Ph/Fax
(02)631 1236.
UHF hand held radios:
Shinwa SH404Kg Band 400-520 MHz,
complete with battery (Nicad) and
battery processor $150.00 each. Phone
(077) 211 935.
Unusual books:
Electronic Devices, Fireworks,
Locksmithing, Radar Invisibility,
Surveillance, Self Protection, Unusual
NEW RATES
EFFECTIVE AUGUST 199G
ADVERTISING RATES
FOR THIS PAGE
SMALL ADS:
The minimum acceptable size of two
centimetres x one column costs only S50.
Other sizes up to a maximum of 10
centimetres are rated at
$30 per centimetre.
CLASSIFIEDS:
S6 for 40 letters. Just count the letters, divide
by 40. and multiply by $6.
Round up to the nearest multiple of S6
Minimum charge SI2
CLOSING DATE:
Ads may be accepted up to the 10th of the
month, two months prior to issue date.
PAYMENT:
Payment by cheque or money order only,
plus your name and address, should be sent
with your advertisement, to:
THE ADVERTISING PRODUCTION
MANAGER
ELECTRONICS AUSTRALIA,
P.0. BOX 199,
ALEXANDRIA, NSW 2015
Chemistry and More. For a complete
catalogue, send 95 cents in stamps to:
VECTOR PRESS, Dept E, PO Box 434
Brighton SA 5048.
Old editions of Radio & Hobbies
and EA:
1939-1949 42 issues, 1950-1959 30
issues, 1960-1969 51 issues 1970-1979
80 issues. Includes: April 1939 Vol 1 No.
1. 1947 & 1950 Shortwave Handbooks,
1975 & 1976 Yearbooks. Send SAE or
call for a complete list. Offers to:
Stephen Stebbing 8/11 Chapel St, St
Kilda, Vic 3182. (03) 510 5987.
I’ve got 80 EPROM emulator
PCBs left:
Normal price $30, now $10! 8031 ’s $2.
P&P $5. This PCB can be used for 8051
development projects too. See EA
Jan/Feb 92. Tantau Australia P.O. Box
1232 Lane Cove 2066. A.H. (02) 878
4715.
Swansea, Tasmania:
3 bedroom house with T.V. & electronics
workshop. Also amateur radio antennas.
Details, 002 578 471.
Sinadder meter,
Vicom model PLM:
with books, cost $1100 sell $300. Solder
in tweeters for surface mounted devices
includes transformer, accessories. New
in box. Never used $150. Ring (03) 354
9991. Joe, PO Box 70, Pascoe Vale
South, 3044.
Technology Breakthrough:
A $20 Programmer Kit for one of the
newest, fastest, low power single chip
EEPROM Micros available. The $15
PIC16C84 can be it’s own downloader
development system as it will re¬
program 1 Meg times, each time in 10
seconds. A $2 coin for my PROMO disk.
Don McKenzie, 29 Ellesmere Cres,
Tullamarine 3043; Ph (03) 338 6286.
TORTECH PTY LTD
TOROIDAL TRANSFORMERS
Design and Manufacture
Approved to AS3108 - 1990 & U.L. Standards
Tel: (02) 642 6003 Fax: (02) 642 6127
Engraved Panels:
Antique or modern look. Any size, your
design. Write or phone for a free sample.
COMPUGRAV Box 941 St. Marys 2760.
Ph. or Fax (02) 623 3598.
MicroCraft Presents:
Dunfield (DDS) products are now
available in Australia. Micro C, the
affordable ‘C’ compiler for embedded
applications. Versions for 8051/52,
8086. 8096, 68HC08, 6809, 68HC11 or
68HC16 $149.95 each + $3 p&h • Now
on special is the SDK a package of ALL
the DDS ‘C’ compilers for $410 + $6
p&h (save $139) • EMILY52 is a PC
based 8051/52 high speed simulator
$69.95 + $3 p&h • DDS demo disks $7
+ $3 p&h • VHS VIDEO from the USA
(PAL) ‘CNC X-Y-Z using car alternators’
(uses alternators as cheap power
stepper motors!) $49.95 + $6 p&h
(includes diagrams) • Device
programming EPROMs /PALs etc from
$1.50 (inc label). We use and
recommend the HILO ALL-07 Universal
Programmer • Fixed price PCB layout &
photoplots. We use and recommend
PROTEL For Windows EDA tools •
Credit cards accepted • Call Bob for
more details MICROCRAFT, PO Box 514
Concord NSW. 2137 (02) 744 5440 or
FAX (02) 744 9280.
Printed Circuit Board Manufacture
We manufacture high quality PCBs at
prices so low, mat it's not worth
making yourself!
INSTANT PCB’s
PO Box 448 Avalon 2107
Ph (02) 974 1189 Fax (02) 974 5491
CHRISTIAN
1245 Burke Rd„
Kew 3101
Established in 1933, RCS Radio is the
only company which manufactures
and sells every PCB and front panel
published in Electronics Australia and ET1/SC.
651 Forest Road, Bexley, NSW 2207
Ring (02) 587 3491 for instant prices.
Kit assembly & repair:
Low rates. Contact Autronics on phone
(08) 294 8591.
KIT REPAIRS - R & D, prototyping, repairs
to electronic equipment, all kits repaired
CA M PA D E L EOT R O N1C S
26 Keith Street Capalaba, Q. 4157
Phone (07) 245 2008
Medical Electronics Company requires
P.C. control software designer
with analog/digital design background.
Please send resume to
4 Clarke St Guilford NSW 2161
WANTED
Any early valve hifi:
Quad, Leak Garrard 301/401, SME,
Ortofon, KT66, KT88, 300B or similar.
Cash paid (074) 491 601.
Magnavox 8-30 Speakers:
new or near new. Also Ferguson OPM1 -
A output transformers, A&R 1932-
175mA power transformers. Contact
Rick via pager 016 378 813 (local call
from anywhere).
Your computer is Australia’s only computer
magazine written for small business
and home users.
Our editorial team is locally written and is
slanted with a ‘hands on’ approach for those
who believe in PCs as a tool to increase
business efficiency and productivity.
On sale at newsagents or call 008 800 933
ELECTRONICS Australia, June 1995
97
50 and 25 years ago ...
'Electronics Australia' is one of the longest running technical publications in
the world. We started as 'Wireless Weekly' in August 1922 and became 'Radio
and Hobbies in Australia' in April 1939. The title was changed to 'Radio,
Television and Hobbies' in February 1955 and finally; to 'Electronics
Australia' in April 1965. Below we feature some items from past issues.
June 1945
Miniature recorder: A recording set
the size of a folding camera, completely
built-in save for a microphone on the
cord, has been developed by a Chicago
inventor.
Powered by a battery receiver and des¬
tined for postwar civilian use, it weighs
only three pounds. It picks up anything
the human ear can hear. Radio and
newspaper reporters are the most likely
users of this midget set.
Pulse-time modulation: Develop¬
ment of a system of pulse time modula¬
tion application to wire and radio,
including broadcasting and television
sound channels, was disclosed at a meet¬
ing of the Insitutute of Radio Engineers
by E. Labin and E.M. Deloraine, of
Federal Telephone and Radio
Laboratories, associate of the Interna¬
tional Telephone and Telegraph Cor¬
poration. It consists essentially in
transmitting information by pulsing of
constant amplitude and duration.
Instantaneous amplitude of voice is
translated into a variation of time inter¬
vals of successive pulses, the rate of
variation corresponding to instantaneous
frequency of signal.
June 1970
Computer for new university: The
James Cook University of North
Queensland, which became autonomous
on April 20, has placed an order for a
large scale PDP-10 time sharing com¬
puter to be installed in October this year.
The computer, to be supplied by Digital
Equipment Australia Pty Ltd, will simul¬
taneously provide multi-language ter¬
minal facilities with multi-programmed
batch operation and, if required, on-line
control of laboratory experiments. Re¬
search, administration and teaching ap¬
plications will constitute the bulk of the
computing workload, but a service will
also be provided for outside users.
Explorer 1 returns: The first US
satellite in space, Explorer 1, re-entered
the earth’s atmosphere over the South
Pacific on March 31 this year. It was
launched on January 31, 1958 on a
Jupiter-C rocket from Cape Canaveral,
Fla. Data from this first flight estab¬
lished the presence of the Van Allen
radiation belts around the earth.
Canadian transmitter: Canada’s first
high power UHF television transmitter
will be installed in Toronto jointly by
the Canadian Broadcasting Corporation
and Marconi this year.
The contract, worth $200,000, was
awarded to the Marconi Broadcasting
Division through the agency of the
Canadian Marconi Company. The
55KW transmitter will be owned and
operated by CBC, and leased to the On¬
tario Department of Education. The
Department will use the transmitter for
the country’s first full time educational
television channel to be inaugurated on
September 1, this year. ❖
EA CROSSWORD
ACROSS
1. One determined to find
and fix faults. (14)
9. Bands of frequencies. (7)
10. Return of spacecraft to
Earth’s atmosphere. (2-5)
11. Qualifying test. (4)
12. Production errors. (5)
13. The brain produces-
waves of about 50Hz. (4)
16. Retransmit. (5)
17. Satellite launchers. (7)
SOLUTION FOR
MAY 1995
19. Brand of consumer
electronics. (3)
20. Voice of upper register. (7)
22. Short electromagnetic
burst. (5)
26. Service provided by TV
station. (4)
27. Former radio pulsed
navigation system. (5)
28. Video programmer, the
G-.(4)
31. Nobel prizewinner,
Guglielmo-. (7)
32. Type of motor. (7)
33. Brand of computer. (5,9)
SBQBUUJQCIDSB □□□
son m h b □
□□□□□□□ □nmansa
a h □ h a o ii n
aaaa aamnn raann
HSU
□huehbb annaam
DOWN
1. Checked operation. (6)
2. Function. (7)
3. Unit of information. (4)
5. Physical units of computer
system. (8)
6. Term often used in older style
radio telephony. (4)
7. Most remote; utmost. (7)
8. Junction at which nerve
impulses cross. (7)
14. Unit of capacitance. (5)
15. Part of an analogue meter. (5)
18. Transverse surface wave. (8)
19. Radioactive element. (8)
21. Initiate energy to a
circuit. (5,2)
23. Constellation with red super
giant Antares. (7)
24. Astronomical length. (6)
25. Examine items in
computer data. (6)
29. Sound of acoustic
feedback. (4)
30. Les-, radio industry
pioneer associated with
Stromberg-Carlson. (4)
4
98
ELECTRONICS Australia, June 1995
NEWS HIGHLIGHTS
NORTH QUEENSLAND
RADIO CONVENTION
The Townsville Amateur Radio Club
Inc will be running this year’s North
Queensland Amateur Radio Convention
at the Western Campus of James Cook
University, in Townsville, on September
16 and 17.
Registration and further information
can be obtained from The
Townsville Amateur Radio
Club at PO Box 5744,
Townsville MC, Queens¬
land 4810.
CYBEC'S 'VET'
IS 0Z LEADER
Mel bourne-based firm
Cybec, specialist in antiviral
computer software, claims that
its well-known package Vet is
now the Australian leader in
this technology. The package
is now used by a very wide
range of universities, TAFE
colleges, schools, research
bodies, Government depart¬
ments and commercial or¬
ganisations large and small,
not only within Australia
but also overseas (including
the UK).
Developed originally by
Cybec founder Roger Riordan,
Vet has been enhanced many
times since it was first
released, and is regularly up¬
dated to ensure that it can deal
with newly developed virus
technology.
The latest version, V8.1, is
Windows and OS/2 com¬
patible and gives on-screen
help and virus information. It can be con¬
figured to provide automatic protection
as well as manual scanning, and is not
only one of the fastest virus scanners, but
also an extremely thorough one. The fact
that Vet is locally developed also en¬
sures that Cybec can offer fast and effi¬
cient support, for Australian users.
Incidentally, Electronics Australia is it¬
self a proud user of Vet , which we use to
check all incoming files — including all
files made available via our Reader Infor¬
mation Service Bulletin Board System.
SHOPPING COMPLEX
BUYS DISKLAVIERS
Sydney’s restored Queen Victoria
Building (QVB) shopping complex has
purchased three Yamaha concert grand
pianos fitted with the Yamaha Disklavier
II electronic recording and playback sys¬
tem, and is using the pianos to entertain
visitors and shoppers with ‘live’ classical
Shown here is one of the three Yamaha concert grand
pianos used to entertain visitors and shoppers in the
restored Queen Victoria Building.
music. The pianos are located on dif¬
ferent levels in the complex but are inter¬
linked via the MIDI system, allowing a
single player to play all three simul¬
taneously — or multiple players to per¬
form together.
The Yamaha Disklavier II system is es-
sentially a modern version of the
‘reproducing pianos’ that were popular
earlier this century, but uses digital
electronics to provide enhanced record¬
ing and playback of all aspects of a
pianist’s performance.
Optical sensors are used to register
every nuance of key and pedal move¬
ment for recording, without interfering in
the least with the piano’s action or
‘touch’. For playback long-stroke
solenoids under the rear of the keys
recreate the original performance, com¬
plete with note velocity and extension.
Other solenoids operate the pedals, for
faithful replay of expression.
Young piano students from
the NSW Conservatorium of
Music, other Sydney schools
and private piano teachers are
being invited to perform on the
pianos at regular recitals.
Also the Disklaviers are used
to play recordings of perfor¬
mances by world famous
pianists, at other times. Perfor¬
mances take place daily at
11.30am and 12.30pm.
1995 ATERB
SCHOLARSHIPS
The Australian Telecom¬
munications and Electronics
Research Board (ATERB) has
again awarded one-year
postgraduate scholarships
(with the possibility of exten¬
sion to three years), to en¬
courage research in the area of
telecommunications. The
scholarships are valued at
$ 11,000 tax-free per year, and
are awarded to students of
Electrical Engineering, Com¬
puter Systems Engineering,
Theoretical Physics and
Telecommunications, at
Australian universities.
The eight scholarship
recipients for 1995, their
university and their respective fields of
research, are:
• Hyunsoo Cho, University of Technol¬
ogy, Sydney, ‘Mechanisms for Sup¬
porting Quality of Services in Dis¬
tributed Multimedia Applications’.
• Benjamin Eggleton, University of
Sydney, ‘Optical Properties of
Holographically Written Bragg Grat¬
ings in Photosensitive Optical Fibre
and Application in Nonlinear Optical
Signal Processing’.
• Martin Evans, University of Technol-
100
ELECTRONICS Australia, June 1995
120MHZ PENTIUM HAS
0.35 MICRON PROCESS
Intel has introduced a new, higher
performance version of its Pentium
processor. The new processor operates
at 120MHz, delivers 140SPECint92
and 103SPECfp92 of performance,
and is available in volume now.
The 120MHz Pentium is the first
volume microprocessor to be built
using 0.35 micron process technology
(a micron is approximately 1/100th the
diameter of a
human hair).
This new tech¬
nology will
allow the Pen¬
tium processor
die to shrink to
half its current
size, which
translates into
higher perfor¬
mance, high
reliability and
lower cost
products for
computer users
in the future.
“The rapid implementation of the
0.35 micron manufacturing technol¬
ogy allows us to expand the Pentium
processor family at an unprecedented
pace,” said G. Carl Everett, senior
vice president. Microprocessor
Products Group.
“The 120MHz Pentium processor
introduces a new level of compatible
performance for mainstream desk¬
top computers.”
“New members of the Pentium
processor family, including a 150MHz
version, will be introduced during the
year,” noted Everett.
Intel’s move to volume
microprocessor manufacturing on a
0.35 micron process technology al¬
lows the die size to be reduced to ap¬
proximately one half the size of Intel’s
Pentium processors built on 0.6
micron process technology (75, 90 and
100MHz) which
was introduced
just last year, or
about one fourth
the size of the
original Pentium
processors built
on the 0.8
micron technol¬
ogy (60 and
66MHz) intro¬
duced in 1993.
Intel’s 0.35
micron process
technology is a
3.3 volt Bi¬
CMOS process
that combines the energy saving fea¬
tures of CMOS technology and the
high performance characteristics of
bipolar technology. The process fea¬
tures four layers of metal and full use
of planarisation (polishing each sur¬
face of the wafer flat before building
the next layer upon it), and is built on
8" (200mm) wafers.
ogy, Sydney, ‘Implementation and
Applications of FCMA’.
• Mark Janos, University of Sydney,
‘Adaptive Photonic Signal Processing
Systems for Telecommunications
Networks’.
• David Lapsley, Curtin University of
Technology, ‘Network Performance
of Access Control Protocol for
ATM Networks’.
• Tanya M. Monro, University of Syd¬
ney, ‘Self Written Waveguides’.
• David Rowe, University of Technol¬
ogy, Sydney, ‘Rapid Prototyping for
Service Verification via Object Orien¬
tated Visual Programming’.
• Kenneth Tan, University of Mel¬
bourne, ‘Narrowband Interference
Suppression in CDMA Spread-
Spectrum Communications’.
ATERB is jointly sponsored by
Telecom Australia, CSIRO and DSTO,
who co-opt academic representatives
from the universities onto the manage¬
ment committee.
PHILIPS WINS MAJOR
PAY TV CONTRACT
BTS Broadcast Television Systems, a
business unit of Philips Electronics, is to
make a multi-million dollar delivery and
installation of the most technologically
advanced digital equipment for the
production and transmission of
Australia’s newest pay TV channels,
Australian Information Media.
The Australian Broadcasting
Corporation’s subsidiary Australian In¬
formation Media (AIM) has recently un¬
veiled its two channel service, with US
based Cox Communications and
newspaper company John Fairfax Hold¬
ings being the main partners. Turner
International’s CNN and Viacom’s Nick¬
elodeon join the party as partners and
programming sources.
The services, which will a include
Australia’s first 24 hour news channel
and children’s programming during the
day, plus drama, documentaries and
general entertainment in the evening, will
begin shortly to subscribers via cable,
MDS or satellite.
BTS won the contract for a total pack¬
age of equipment for the service’s new
studio complex at Gore Hill in Sydney.
The complex will include news and
current affairs studio and will feature key
products from the BTS range including
the LDK 10P series cameras, the DD20
production switcher, the Saturn presenta¬
tion switcher, the Venus router, the
Jupiter control system and the Alamar
automation system.
The BTS concept is based on a total
equipment integration from production to
distribution. The ground-breaking, fully
digital installation is totally future proof.
Even the picture aspect ratio can be
changed from normal 4:3 to 16:9
widescreen at the touch of a button.
TELSTRA BUYS $4M
IN TEK TOR'S
Tektronix has been awarded a three
year contract to supply its TS100 Tel-
Scout Time Domain Reflectometers
(TDR) to Telstra. The Telstra contract is
estimated to be worth $4 million to
Tektronix over the next three years.
The TelScout TS100 combines un¬
precedented ease of use, high perfor¬
mance, rugged packaging and
competitive price with a feature set op¬
timised for telephony. It tests both twisted
pair and coaxial cables.
Unlike products that require operators
to navigate through multiple menu levels
as they select a range of test criteria, the
one step set-up and operation of the Tel¬
Scout is highly automated, requiring
Telstra technicians only to identify the
cable type to obtain a waveform.
GRIFFITH UNI TO
SCAN HISTORIC PICS
Historical photographs held in the State
Library in Brisbane should be accessible
by all Queenslanders within two years,
under a plan to digitise the prints and
make them available on CD-ROM.
The first stage of the project, which is
to investigate and evaluate available tech¬
nology, is being carried out by the State
Library in cooperation with the Griffiths
University’s School of Microelectronic
Engineering Industrial Affiliates
Programme (IAP).
The IAP provides industry with under¬
graduates in the Bachelor of Engineering
in Microelectronics Engineering degree
ELECTRONICS Australia, June 1995
101
NEWS HIGHLIGHTS
course with an opportunity to work on
important research projects with an in¬
dustrial partner.
Student Steven Chamberlain will lay
the groundwork for the introduction of
the new system, which initially will in¬
volve about 20,000 historical photo¬
graphs. Steven is responsible for in¬
vestigating technology options,
liaising with suppliers,
evaluating systems and recom¬
mending the technology,
which aims to eventually
provide State-wide access to
the 750,000 historic photo¬
graphs in the collection.
Griffith University (IAP) is
also involved in a research
project to optimise Queens¬
land’s only stereolithography
facility at the Queensland
Manufacturing Institute.
Stereolithography is a three
dimensional modelling process
which produces copies of 3D
CAD solid or surface models
in plastic.
The process uses a moving
laser beam, directed by com¬
puter, to ‘draw’ cross sections
of the model onto the surface
of photo-curable liquid plas¬
tic. It can make prototypes of
products and components in
hours instead of the days and
weeks required by traditional
manufacturing processes.
The upgrading involves
remote monitoring and control
of the machine to ensure that
the manufacturing process
does not shut down suddenly
in the event of a power prob¬
lem, delaying production by up
to several days. Instead, the
computer controlled apparatus
senses a power corruption, car¬
ries out a controlled shutdown,
and allows manual resumption of produc¬
tion when power is restored.
The project, which began last year, is
being continued by Griffith University
student Raymond Clarke, under the IAP.
Raymond is carrying out the final stages
— completing the software, checking the
performance of the UPS, and developing
monitor software.
The IAP provides undergraduates in
the Bachelor of Engineering in
Microelectronic Engineering degree
course with an opportunity to work on
important research projects with an in¬
dustrial partner.
0Z BREAKTHROUGH
IN DATABASE ACCESS
Australian-owned ACEL Information
Pty Ltd has leapt onto the informa¬
tion superhighway with CD-CON-
NECT, a new system which will
provide instant, networkable access to
massive image databases. It is the
product of more than 12 months’ work
by a team of 10 specialists.
Combining expertise in CD-ROM
technology, ISDN and advanced com¬
puter software, the ACEL team has in¬
tegrated the potential of each of these
technologies, thus overtaking the major
multi-national information suppliers.
ACEL’s members use a CD-ROM as
an index to conduct all their searches.
Required documents are automatically
retrieved via Telecom’s ISDN. ACEL
believes its DC-CONNECT technology
is the first commercial ISDN application
for information transfer from a data
provider to its hundreds of customers. As
such, it represents a breakthrough for
ISDN as well. According to Technical
Director Richard Barber, it is impossible
to transmit this kind of image data
through ordinary analog phone lines at a
worthwhile speed.
“Of course, we found that ISDN in it¬
self did not solve all the problems of ob¬
taining instant access to our large image
data bases. But it provided the founda¬
tion,’’ Mr Barber said.
The rest of the solution was in software
developed by ACEL to smooth
the way for users to enjoy con¬
venient access to the informa¬
tion, while minimising the
connect time. With ACEL’s
solution, information can be
downloaded almost instantly to
the user’s computer. ACEL’s
software enhancements have
greatly increased the speed at
which ISDN works.
Further, ACEL’s Windows
interface makes the whole
process seamless and automat¬
ic. There are no complicated
login/logout procedures. The
main reservoir of data will
be held in ACEL’s computers.
An updated index CD will
be supplied regularly to
ACEL’s customers.
“If our customers were to
have all the data in CD-ROM
format, it would require 60 to
70 CDs, with all the attendant
problems of networking and
storage,” Mr Barber said.
“They would need to install
a jukebox which slows ac¬
cess time, and is prone to
mechanical problems. Or, they
could daisy chain dozens of
CD drives, which would be
terribly expensive. In short,
they wouldn’t get many of
the benefits of electronic
delivery.”
ACEL plans to offer CD-
CONNECT to its Australian
customers during 1995 and has
begun looking at export opportunities in
Europe and South East Asia.
SMART CARD FOR
NSW TRANSPORT
Australia’s first contactless transport
smart card. Transcard has been launched,
enabling consumers to use the one ticket
to travel on any mode of public transport
— from train to bus to taxi.
Transcard also enables consumers to
make small purchases using the one plas¬
tic card.
The introduction of Transcard began
Students at the School of Cognitive and Computing
Sciences at the University of Sussex, UK, are using
this experimental robot, dubbed ‘Mr Chips' to evolve
new designs for robot control using neural networks.
The students are studying insect behaviour to under¬
stand the mechanisms underlying intelligent activity.
Mr Chips uses a lap-top PC as its brain '.
102
ELECTRONICS Australia, June 1995
Royal Melbourne Institute of Tech¬
nology TAFE is joining forces with
Footscray Girls Secondary College to
provide Year 11 and 12 VCE
electronics training at RMIT’s city
campus. A group of Year 12 students
have done some of their VCE physics
work in the TAFE Department of
Electronics Technology in first
semester, while during second semester,
around 20 Year 11 Physics students will
join RMIT’s electrical/electronics As¬
sociate Diploma classes for the subject
‘electrical fundamentals’, for half a day
each week. The secondary school will
conduct the assessment, in consultation
with RMIT staff.
RMIT’s TAFE Equal Opportunity
Manager, Ms Anne Holland, said that
the project will have two significant
benefits. It will provide the students
with access to RMIT’s facilities, and it
will encourage the girls to consider
electronics as a career option.
“Girls are significantly under-repre¬
sented in the electronics course,” she
said. “This project will allow them to
see that RMIT is a good place to come
to study. They will have a positive ex¬
From left: RMIT teacher Klaus Bienert, 1st year RMIT student Betty Gene and
VCE students from Footscray, Lily Wuam and Suzie Todovoska.
perience in the subject; and they will
feel comfortable here, so it might en¬
courage them to undertake further train¬
ing in electronics and consider TAFE as
an option for further studies.”
The Head of the TAFE Department
of Electronics Technology, Mr Ian
Hood, said that the project is part of a
strategy to increase the number of
female applicants into the electronics
course. “People are more likely to
choose subjects they have some
knowledge of,” he said.
Mr Hood and Ms Holland addressed
Year 10, 11 and 12 students from the
Footscray school last year. As a result,
two have begun the Associate Diploma
of Electronics this year.
For course information, call (03) 660
4425.
with a three month trial in Sydney’s west,
to be followed by a national roll out from
July 1995. Transcard’s Chairman, Mr
Reg Kermode, said that Transcard will
make public transport more convenient
and accessible.
“Transcard goes one step further than
other smart cards. It not only offers a
ticketing and payment system on the one
anonymous card, but it also uses contact¬
less technology.”
There are no slots or PINs with
Transcard. A microchip and antennae in a
standard sized plastic card ‘talks’ via
NEWS BRIEFS
radio signals to a card reader, without
physical contact. Consumers simply tap
the card reader to pay. The Transcard in¬
built microchip processes and stores in¬
formation, allowing the consumer to buy
and store tickets as well as load and
spend electronic cash (like a reusable
phone card) for travel and small pur¬
chases such as newspapers or fast food.
When the balance runs low. Transcard
can be topped up by using either cash,
credit or EFTPOS, at any Transcard
agency which includes newsagencies and
other outlets.
SMPTE '95 FOR
DAR1IN6 HARBOUR
The SMPTE ’95 Exhibition and Con¬
ference is to be held at Darling Harbour
from July 3 -6, 1995. Leading innovators
in the sound and picture industries from
around the world will be showcasing the
latest in new equipment in film and
television engineering. Exhibitors include
Sony Australia, GEC Video Systems
Division, Amtech, Techtel, Amber and
Hagemeyer.
The SMPTE ’95 Exhibition will fea¬
ture new product and equipment
launches, including the release of the new
Australian production music library. The
Soundtrax Music Library from the
Nightlife Music Group.
To commemorate the launch, the com¬
pany is also giving away a Ken Duncan
limited edition print.
1995 is the first SMPTE exhibition and
conference to follow the rescheduling of
the bi-annual event to odd years, better
positioning SMPTE within the interna¬
tional programme of events.
A different style of conference will
support this year’s exhibition. The con¬
ference programme will be structured
around six half day seminars. ❖
* ?!?L Communications has announced the appointment of Mr Greg Dyer to the newly
created post of Logistics Manager for Asia Pacific ^
* how lV^°u 9 K °£ 9 lnt ® mational Computer Expo Systems show Computer ’95 will be
held at the Hong Kong Convention and Exhibition Centre from May 24-27 1995 For
more information contact Business & Industrial Trade Fairs, 18/F First Bank’Centre 56
Gloucester Road, Wanchai, Hong Kong, phone (852) 2865 2633.
* Optical Systems Design has moved to 7/1 Vuko Place, Warriewood, Sydney 2102. The
PO box, phone and fax numbers remain the same
* representa,ive and dis,ributor f °' CIS Corporation,
* ofSun Microsystems 60 appointed Mana 9' n 9 Director of SunSoft Australia, a subsidiary
* cmJ Mafl ha 'i Computer and Communication Marketplace will be held in the Queen
Sirikit National Convention Centre, Thailand, November 23-26, 1995. For more informa-
(662) < 2i n ^MM iai «> Trade Fa ' rS 822/1 Rama Vl R ° ad ’ Phyathai ' Bangkok 10400, phone
ELECTRONICS Australia, June 1995
103
Mini Construction project
pr.haQPri
68705K1 Programmer
This low cost project has all you need to get into programming the Motorola 68HC705K1
mtarocontroiier. The project includes all the hardware and software, yet ,t costs around $70. Now
you’ve no excuse!
by PETER PHILLIPS
This very simple project comes from
Robert Priestly, the designer of the
Motorola 68705 microcontroller
development system presented in EA for
March 1993. This previous system in¬
cluded a versatile software package and
a programmer board to accept a range of
68705 microcontrollers.
Then in July ’94, we reviewed an en¬
hanced version of this system, which
included additions to the software and
the capacity to program a wider range of
Motorola microcontrollers. This new
system has won widespread acceptance,
and is being continually upgraded.
However, while a system that can
program a range of microcontrollers
is versatile, it’s often overkill if you
only want to program one type. And
that’s where this ‘mini’ system comes
in. It’s intended for the 68HC705K1
series only, which is why the
programmer PCB is so small. So, first
let’s take a brief look at the ’K1
microcontroller, as the whole project is
based around this device.
The 68HC705K1
Like all members of the Motorola
microcontroller family, the 68HC705K1
DB25
si
+120 DC
D 1
-H-
1N4004
IC2
78L05
1, °--t
; C2
0. luF
(POWER )
STROBE 1
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2T"
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+ 20U
R5
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I OK a
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. luF |
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R7
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+16.8U
Z1
1N4740
10U
22
(rir)lN4736
6.8U
T
S2
—o^o—
(UPP)
R8
2.2k
C6
T lOuF
0
I RQ/VPo
>
0SC2
0SC1 -
PB0 -
PB1/03 -
RESET :
V/l
PA0 -
P A 1
PA2
P A 3
PA4
PA5
P A 6
in
PA7
z>
R2 ,
470 ,
R9
2.2k
Ini I—►
0CK
STROBE ^
TT~
12U to 20U converter
The programming voltage (Vpp) is developed by the circuit around IC3. The board interfaces to an IBM compatible
computer via its parallel port, and the programming process is controlled by the computer software.
104 ELECTRONICS Australia, June 1995
Instruction Set
(Ut-F3 Close F5 Zoom F6 Next FtHlssenble
0^11111111
BRCLR INC
BRN JHP
—Mlt—Search Assemble Options Uinrinus He!
^nstrulunn^Vt vT e£Wor screen ’ with a superimposed window with the
instruction set of the K1 microcontroller. The complete data on the K1 is
included in the software package.
is available in two versions: one with
one-time programmable read-only
memory (OTPROM) and the other with
erasable PROM (EPROM) memory. The
latter is more expensive at around $40 to
$50, but is essential for development
purposes, as it can be repeatedly erased
for ‘another try’.
The OTPROM version however is
much cheaper, at around $6 to $8. But
because you only get ‘one go’ at
programming it, this version is
programmed only when your software
has been fully developed. So ideally,
you need one EPROM version to test
the software you're developing, and an
OTPROM version for each declared
function you develop.
The 'K1 is a 16-pin microcontroller,
which makes it unique in the Motorola
family as all other devices have at least
20 pins. It has 504 bytes of EPROM,
32 buytes of RAM and 10 bi-direc¬
tional I/O pins in two I/O ports. Port A
has eight I/O lines and port B has two.
Four of the I/O lines can sink up to
8mA, to drive a LED or similar. Four
more lines can be programmed as
maskable interrupts.
The ’Kl features static operation,
which means there’s no minimum
clock speed. The clock can be any¬
thing from a single-stepped switch
(debounced, of course) up to a 4MHz
crystal controlled oscillator. The chip
has its own on-board clock oscillator,
which can be configured as either a
crystal or an RC oscillator.
The system
As with the previous systems, there
are two parts: a build-your-own
programmer board (as in the photo), and
IBM compatible computer software sup¬
plied on a disk with the kit. The board
plugs into the parallel port of the com¬
puter, via a DB25 plug on the PCB. The
only other external connection is a
+ 12V DC supply, from either a DC
plugpack or any external DC supply.
To program a 'Kl microcontroller,
you simply insert it in the socket on the
programmer board, and press a few
computer keys to make the software do
the rest. We’ll describe this PCB in
more detail later, but first a look at the
software that comes with the system.
The software
Like Robert's previous development
systems, the software that comes with
this one includes the Motorola freeware
cross-assembler, a software simulator
and the software to drive the program¬
mer PCB.
We won’t describe this software here,
as it’s been covered in detail in the pre¬
vious articles. For more information,
refer to either the July ’94 or the March
’93 editions of EA.
But unlike the previous versions, this
new package also has an on-line text
editor that — believe it or not — in¬
cludes the complete ’Kl data manual.
That’s right, you get all the instructions,
specifications and so on, right at your
finger tips, and right where you most
need it. The text editor is used to write
the source code, which is then passed to
the cross-assembler where it’s as¬
sembled into hexadecimal code.
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READER INFO NO. 21
ELECTRONICS Australia, June 1995
105
PC-based 68705K1 programmer
Here’s the layout diagram of the PCB. The board is
double sided so there are no links to it.
This is the programmer board for the 68HC705K1 Motorola
microcontroller. It plugs into the parallel port of the host
computer.
The screen shot in Fig.l shows a pro¬
gram listing as it appears in the text
editor, but with the complete instruction
set of the ’K1 controller superimposed
in another window. This feature alone is
probably enough for any frustrated
programmer to want this software!
The mouse-driven text editor also fea¬
tures an almost Windows-like interface,
with movable and sizable windows.
There’s an extensive help file, a clip¬
board (which can be viewed), and a host
PARTS LIST
Resistors
All 1/4W:
R1,2 470 ohm
R3 220k
R4 10k
R5 1 ohm
R6,7 180 ohm
R8,9 2.2k
Capacitors
Cl-4 0.1 uF ceramic
C5,6 lOuF 25V RB electrolytic
Semiconductors
LED1 green 5mm LED
D1 1N4001 diode
Z1 10V 1/2W zener diode
Z2 6.8V 1/2W zener diode
IC1,2 78L05 3-terminal 5V regulator
IC3 78S40
Miscellaneous
Silk-screened PCB, 60 x 65mm;
10mH inductor (II); 16- pin 1C socket
for K1 microcontroller; 16-pin 1C sock¬
et for IC3; PCB mount DB25 plug;
3.5mm PCB mount phono socket;
12V DC plugpack; softare disk; two
PCB mount two-way slide switches.
of commands normally only found in a
word processor. For instance, the mouse
can be used to select blocks of text for
copying to the clipboard, and there’s
commands to search and/or replace text.
The manual for the system is also
on the disk, along with numerous
sample programs you can use to either
experiment with, or as part of your
own programs.
So, the development process starts
by producing the source code with the
text editor, after which it’s converted
into Motorola’s .S19 format using the
cross-assembler. The program is then
tested in the simulator. Once every¬
thing works as it should, the K1
microcontroller to be programmed is
plugged into the programmer PCB and
the programmer driver software is
called up to do the rest.
Programmer PCB
The circuit of the programmer PCB
is shown in Fig.2. As you can see,
there’s not much to the circuit, as most
of the work is done by the program¬
mer software.
The 12V DC supply to the board is
fed to IC2, where it’s regulated to give a
+5V supply. The 12V input also powers
the switching regulator around 1C3,
which produces a 20V DC output at pin
1. This voltage is regulated by zener
diodes Z1 and Z2 to give a program¬
ming voltage of 16.8V for the ’K1 being
programmed (IC1).
The interface to the parallel port of
an IBM compatible computer is via an
on-board DB25 plug and a standard
DB25 printer cable. The eight data lines
(DO to D7) transfer data to the 'K1
being programmed, and the remaining
lines provide control and communica¬
tion between the programmer and the
computer.
In summary
Because this project is similar to the
previous 68705 development systems by
Robert Priestly, we have only described
those parts that are unique to this
project. To get a better idea of the ver¬
satility of the system, refer to the pre¬
vious articles. And at around $70, surely
this has to be the most cost effective
'K1 microcontroller programming sys¬
tem we’ve ever described ♦♦♦
KIT AVAILABLE
A kit of parts for this project is avail¬
able from:
Oztechnics
PO Box 38,
lllawong, NSW 2234.
Phone (02) 541 0310
Fax (02) 541 0734
Email oztec@ozemail.com.au
’K1 development system, PCB, on¬
board components and all software
as described $70
’K1 microcontroller IC, POAHC05
applications guide and ’K1 data
books also available.
Microcontroller kit as reviewed
in EA July’94 $280
P&P $7
106
ELECTRONICS Australia, June 1995
NEW PRODUCTS
PCB mount switches
A new series of PCB mount switches
has been released by Diptronics. In¬
cluded is a range of rotary DIP switches,
which measure 10 x 10mm. These are
available with flat or high actuator and in
surface mount or through-hole versions.
Other switches include a range of
tactile switches. Available in right
angle and ground terminal types, they
feature a sharp ‘click’ feel when
pressed. Insert moulding in the contact
combined with special treatment
prevents flux build-up during soldering
and permits auto-dipping.
For further information circle 242 on
the reader service coupon or contact
Adilam Electronics, 3 Nicole Close,
North Bayswater 3153; phone
(008) 800 482.
Audio line and
speaker switch boxes
Altronics has available a new range of
switch boxes for stereo audio or speaker
switching. The switchers include a four¬
way line switcher (audio signals only), a
two-way speaker and input selector, and
two-way and four-way speaker switch
boxes. The four-way input selector al¬
lows any one of four stereo audio inputs
to be switched to a stereo input of an
amplifier, and is priced at $37.50. The
two-way speaker switch and input selec¬
tor includes two independent stereo
speaker switches, and automatically
maintains correct impedance at the
amplifier speaker output. This unit also
selects either of two auxiliary audio in¬
puts via a rocker switch on the front
panel. It has an RRP of $49.50.
The two-way speaker switch box has
two independent stereo speaker switches
and automatically maintains correct im¬
pedance at the amplifier speaker output.
It includes spring clip terminals for easy
speaker wire connections and costs
$39.95. The four way speaker switch box
is similar, but has four independent
stereo speaker switches. It costs $49.95.
For further information circle 241 on
the reader service coupon or contact
Altronics, 174 Roe Street, Perth, 6000;
phone(09)328 1599.
MATV amplifier
The 905 series television amplifier sys¬
tem, designed and manufactured by
Alcad of Spain, is a low cost, single
channel amplifier system that allows the
level of each channel to be adjusted inde¬
pendently, so uniform output levels are
delivered into a multiple outlet antenna
system in a large house or block or units.
The introduction of a low power UHF
channel 31 service in some major
Australian cities has increased the need
for this type of system.
A feature of Alcad’s 905 series is an
inbuilt signal measurement system,
making installation easier. The series also
has inputs for satellite IF and 88-
108MHz FM.
A combined mounting rack and power
supply is used to mount up to seven
single channel amplifiers on one rack,
with two inputs for either five and two or
four and three channels. One configura-
Microwave oven has word prompting
The new NNC855B microwave oven from Panasonic has
a word prompting feature that instructs the user via a scrolled
message on the display screen. In total there are over 50
instructions programmed into the oven, covering every fea¬
ture of operation including how to program recipes, how to
use auto defrost and reheat, how to set the clock, and even
prompt action during a cooking cycle. Word prompting al¬
lows the oven to be used immediately, without having to
refer to the instruction manual.
The new oven has four different cooking modes:
microwave; convection; grill and combination. Combination
combines the speed of microwave cooking with the crisp,
brown cooking results of traditional convectional cooking.
It has a 1300 watt quartz element which preheats instan¬
taneously (no reheating required) and is able to ‘flash brown’
and grill foods. Another 1400W element at the rear of the
oven has a fan for air circulation, for baking. The oven also
has 900 watts of microwave power and a capacity of 32
litres. The new see through door allows the user to easily
observe the contents of the oven without opening the door.
The oven also incorporates the ‘Genius’ sensor which
allows the user to program the entire cooking cycle for
popular foods such as chicken, vegetables, rice and fish.
The RRP is $769.
For further information contact Panasonic’s Customer
Care Centre on 132 600.
ELECTRONICS Australia, June 1995
107
READER INFO NO. 22
Hot jet handpiece
Royston Electronics has introduced
the Royel HJH100 hot jet handpiece.
The unit is suitable for reflow solder¬
ing, solder paste reflow, with particular
application to surface mount circuitry,
testing components and for actuating
heat shrink tubing.
The handpiece can be operated from
the HJ1000 variable air flow and digi¬
tal feedback controlled power unit, or
any of the Royel Thermatic desolder¬
ing/soldering stations. It has an N type
thermocouple sensor at the base of the
delivery nozzle, which allows a con¬
tinuous digital readout of the actual
air/gas flow temperature.
Designed for use on electronic cir
cuits and specifically for surface mount
circuitry, the handpiece is made from
static dissipative air/gas feeding tube to
avoid electrical damage to components
or circuitry.
For further information circle 246 on
the reader service coupon or contact
Royston Electronics, PO Box 328,
Mount Waverley 3149; phone (03) 543
5122.
tion has four modules on one input for
channels 2, 7, 9 and 10, with three
modules on the second input for channels
28, 31 and 0 for in-house VCR, etc.
For further information circle 243 on
the reader service coupon or contact
Peter C. Lacey Services, 80 Dandenong
Road, Frankston 3199.
Code changing
vehicle alarm
The Securicode is claimed to be an
ultra-high security vehiclar security sys¬
tem. Its main feature is its innovative
(and patented) code changing technol¬
ogy. With the ever increasing use of code
learning devices (as used by a majority of
professional car thieves), anything using
remote control operation with a fixed
code is not secure.
Securicode has codes changing con¬
tinuously and automatically in a
synchronised way, between transmitter
and receiver.
Not to be confused with ‘code
hoppers’ (which are not immune from
being bypassed electronically),
Securicode is microcontroller based and
all functions are software driven. When
coupled with effective immobilising cir¬
cuits, the units offers a very high level of
vehicle protection.
For further information circle 247 on
the reader service coupon or contact
Securicode, 4/810 Princes Highway,
Springvale 3173; phone (03) 548 3300.
Burnishing and
cleaning tools
The Eraser Company has announced
its new model El 00/C and E/100F
fibreglass cleaning and burnishing
tools. These are refillable cleaning
tools used in the same manner as a pen
for applications like contact cleaning,
removing rust spots, erasing printing on
components etc. The tools use inter¬
changeable refills for more aggressive
cleaning action, while the E100/F con¬
tains a fine grade refill for more sensi¬
tive cleaning applications.
The body of the tool is plastic, with a
see through barrel to allow the operator
to see when the refill needs replacing.
RADIO COMMUNICATIONS & GENERAL PURPOSE TEST EQUIPMENT SALE
□ Digital Storage CRO HP 54111D, 2 Channel. 2 Giga Samples/Sec, 500 Mhz Bandwidth,
8Kb Memory, in excellent condition.
□ Communication Service Monitors including - MARCONI 2955/A/B; IFR 500, I000S.I200S;
MOTOROLA 2200, 2400; SYSTRON DONNER.
□ Spectrum Analysers; CRO's; Signal Generators; Power Supplies.
□ RFI Screened Rooms, 8ft x 4ft, S100 and 8ft x 8ft, S200.
All equipment used, calibrated and in very good condition.
NATA calibration available. SURPLUS EQUIPMENT BOUGHT.
SALES, SERVICE, REPAIRS & CALIBRATION OF COMMUNICATION EQUIPMENT AND
’ INSTRUMENTATION TO THE ELECTRONICS INDUSTRY IN GENERAL
CONSULTEC ELECTRONICS
83 Flinders Street, Mentone VIC 3194
PO BOX I 161, South Melbourne VIC 3205
Ph: (03) 585 I 159 Fax: (03) 584 1169 Mobile: 018 033 573
The length of the exposed brush is adjustable by a knob on
the top of the body. The tools are colour coded blue for coarse
grade, and red for fine grade. They are 95mm long; the cleaning
tip is rectangular and measures 17.9 x 3.1mm.
For further information contact The EraserCompany, PO Box
4961 Olivia Drive, Syracuse, New York 13221; phone (315)
454 3237.
Temperature controlled
desoldering solder pot
Royston Electronics has introduced a feedback temperature
controlled version of its reliable all lead reflow desoldering
unit, which has simplified the task of removing and replacing
thru-hole multi-pin packages.
Each of the heads has milled grooves, corresponding to
dual-in-line component pitch, along which resin cored solder
is melted, prior to immersion of the component to be
removed. Reflowing the solder on each pin in a multi-pin
package, prior to withdrawal, avoids the possibility of pulling
out the metallisation in a plated-thru hole, which may not have
been brought to the molten stage after the application of a
vacuum desoldering tool.
A one ounce solder pot crucible can be substituted for one of
the all lead reflow heads, to facilitate pre-tinning of fine lead
components at minimum temperatures to avoid loss of lead
material by dissolution in the tin content of the solder. The
pre-tinning of gold plated heads, which otherwise will cause
solder joint embrittlement, can also be performed.
For further information circle 249 on the reader service
coupon or contact Royston Electronics, 27 Normanby Road,
Notting Hill 3168; phone (03) 543 5122, fax (03) 544 4894.
High quality DIP switch
The Eeco 4600 ‘Minidip’ series is a second generation dual-
in-line design, which is end stackable for ease of PCB layouts.
Available in four through 10 positions (including odd numbers)
and 12 positions, the 4600 series features a self cleaning, four
point bifurcated wiping action which gives greater contact in¬
tegrity, reliability and most importantly, greater increased
switching and non-switching current handling capacity per pole
than is normal for ordinary DIP switches. This feature, com¬
bined with low contact resistance, makes it well suited to data
communications and telecommunications applications, as well
as other demanding designs.
Options include a sealed or unsealed package and three
lead configurations; gullwing or ‘J’ leads for surface mount¬
ing, or standard machine insertable leads. Naturally, the 4600
series is suitable for standard automated desoldering and
cleaning techniques.
For further information circle 250 on the reader service
coupon or contact Philips Components, 34 Waterloo Road,
North Ryde 2113; phone (02) 805 4455.
Efficient 60 watt DC/DC converter
Power Convertibles has introduced a new family of DC/DC
converters, claimed to offer the highest efficiency in its class.
The VKP60R provides 60 watts in a 58 x 61 x 11mm package
and operates over a 36 - 72V DC input supply range, making it
ideal for telecommunications and battery operated applications.
Available DC outputs are 3.3V, 5V, 12V, 15V, 24V and 28V.
Typical efificiences are 84% at 3.3V, 88% at 5V and 91 % at 15V.
The series operates at full power up to a baseplate tempera¬
ture of 100°C and is isolated from input to output with a 1500V
DC barrier. Both load and line regulation are specified as +/-
0.05% maximum over all load and line conditions, and all units
are protected against output overvoltage and overcurrent condi¬
tions as well as baseplate overtemperature.
For further information circle 248 on the reader service
coupon or contact Kenelec, 2 Apollo Court, Blackburn 3130;
phone (008) 335 245. ❖
ijove With The Tims
TKTIinillC
inirunK
■■■■■■■■■■■TECHNOLOGIES CORP.
• 230V AC Power from your battery, any where any time
• Presisely Regulated output voltage is suitable for
sensitive electronics
• 12 or 24 volts input available
• Whether you are out in the field servicing, or need the
flexability of a mobile office, Statpower can deliver.
• Available with outputs from 150 watts tol 500 watts
• Also Truecharge micro processor controlled battery
chargers from lOamps to 40amps
M ■ W~MM W LI1 AUSTRALIA
Unit 2/77 Shore Street, Cleveland Old. 4163
Phone (07) 821 3983 • Fax (07) 821 3977
ELECTRONICS Australia, June 1995
109
READER INFO NO. 23
Solid State Update
KEEPING YOU INFORMED ON THE LATEST DEVELOPMENTS IN SEMICONDUCTOR TECHNOLOGY
IDE interface
for 8-bit CPUs
Palmtech’s PT IDE802/803 devices
are single chip IDE (hard disk drive) in¬
terfaces for 8-bit CPUs. They incor¬
porate an additional 8-bit uni/
bidirectional parallel port plus ten (11
for the ’803) handshake or extra I/O
lines, suitable for implementing a
printer port. They also include a con¬
troller for three interrupts (two for
the ’803).
The eight to 16-bit data conversion is
fully transparent, with an IDE sector ac¬
cessed as 512 8-bit bytes rather than 256
16-bit words. The devices accept any
IDE drive conforming to the CAM ATA
standard, and do not need external buf¬
fering to the drive or printer.
They can be coupled to most 8-bit
CPUs with little or no extra glue logic.
The chips are available in a 68-pin
PLCC package and use 100mA at 5V.
They add 75ns to the IDE drive access
time and cost $55 in single quantities.
For further information circle 277 on
the reader service coupon or contact
Palmtech, cnr Moonah and Wills
Streets, Boulia, 4829; phone (077)
463 109, or fax (077) 463 198.
EPLD has 12,000 gates
Altera has released the 560 macro¬
cell EPM9560, the first and largest
member of Altera’s new MAX9000
family of EPLD devices. With 560
macrocells and up to 216 I/O pins, this
12,000 gate device is claimed to pro¬
vide more than twice the density of the
Solid state switches
for analog line cards
The new ATTL754X family of solid
state switching devices generate no
impulse noise during a ringing
cadence, and thereby eliminate the
need for the zero current switching
typically needed with older generation
relays. The combination of very low
and matched on-resistance is claimed
to simplify circuit board design. The
ICs consume around 15mW and fea¬
ture built-in current limiting, thermal
shutdown and subscriber line interface
circuit (SLIC) protection.
The ATTL7541 solid state ringing
relay is a ‘2 Form C’ relay designed to
provide power ringing access to tip
and ring in any analog line card ap¬
plication such as central office equip¬
ment, digital added main line, digital
loop carrier, hybrid fibre coax and
fibre in the loop line cards. It is pack¬
aged in a 16-pin DIP or SOG.
The ATTL7542 tip/ring access
switch contains the functionality of
two 2 Form C relays that provide
power ring and line access functions,
all controllable by two logic input
levels. It is packaged in a 16-pin SOG.
The ATTL7543 line card access
switch contains the functionality of
three 2 Form C relays in a single pack¬
age. It is typically used to support
power ringing, line access SLIC test
access and ringing generator test ac¬
cess, all controlled by three logic in¬
puts. It is packaged in a 24-pin DIP.
For further information circle 271
on the reader service coupon or con¬
tact Zatek, PO Box 397, West Ryde
2114; phone (02) 874 0122.
110
ELECTRONICS Australia, June 1995
S EPLD ava ‘lable today. Features
" C ' Ude ‘"-system programming
JTAr a m H ,X D^ VOlta8e 1/0 operation,
JTAG and PCI compliance.
ISP makes design prototyping and
production easier by eliminating device
handling. Since the devices can be
programmed on the production board,
• ^ e J moves the programming step
simplifying the manufacturing flows.
ISP also enables a mechanism for field
design upgrades.
Designs can be revised in the field by
r °; m n ' 0a ,n « " ew ^vice configurations
from data links such as modems and
system networks.
For further information circle 276 on
Velte e k ad l8 S H rVi t e C c Up ° n or contact
veitek IS Harker Street, Burwood
3125; phone (03) 808 7511.
S'*i',r iainsPCperii,tai —
The development kit provides cus
tom,sable PCI interfaces for periS
designs such as graphics controllers and
multimedia applications. Additionally
a ? ATM mmUn ' Catl0ns a PP lica tions such
as ATM networking systems are using
rU to increase throughput.
For further information circle 274 on
^ 1 ^ 18 ^^ C e Up0 " 0r contact
y, e “ ek ’ 18 barker Street, Burwood
3125; phone (03) 808 7511.
Gas sensor
750MHz op-amp
PCI development
kit for PLDs
has announced the
availability of a PCI (peripheral com¬
ponent interface) development kit for
pi S !vY' th members of Altera’s
^ max 700 °- flex 8000
and MA X 9000 families of program-
mable logic devices (PLDs).
The kit includes technical information
for designing with this latest industry
standard bus architecture, along with a
PCI develop ment macrofunction dis-
SSR Is form
factor compatible
Electron ics has released
the G3R series of solid state relay
packaged in the same form factor
and footprint as the G2R
electromechanical relay.
AC versions (with or without
zero-crossing function), and DC
versions are available in PCB or
The Figaro gas sensor is a solid state
device mainly composed of sintered tin
dioxide, which detects gases through an
increase in electrical conductivity when
the reducing gases are absorbed on the
sensor s surface. The device is claimed
to have excellent stability and perfor¬
mance, and important features in gas
detection. 5
Features include long life and good
reliability, high sensitivity, quick
response, high resistance to poisoning,
excellent durability, large output signal
and low cost.
For further information circle 272
on the reader service coupon or con-
tact Adi lam Electronics, 3 Nichole
W 8 S rsoo" 82 BaySWa " r 3 ' 53; P "° m
plug-in terminations capable of
switching up to 2A with 2,500V AC
isolation. The SSRs can be ordered
with LED indicators.
Sockets for chassis, DIN-rail and
FLB mounting are available.
For further information circle 273
on the reader service coupon or con-
tact DGE Systems, 103 Broad-
meadow Road, Broadmeadow 2292-
phone (049)61 3311.
Cnm CLC44 c°,' S the latest Edition to
Coml.nears CLC44X series of high
speed monolithic op-amps. The op-amp
( 1500V/ S tH ? SpCed ° f current Redback
j00V/us slew rate and 750MHz unit
wm ,he vers “ iU * of
pJnTrf inClU , de Very low differential
n noso ff fy ential phase of 0.015% and
U.025 . Also, the chip provides wide
dynamic range applications with very
? sK 4 fT n ° niC distortion: (above 70dBc
at -r^ Hz Wlth 3 2V P/P output signal)
OOrnf d / vice Can also deliver "P to
90mA of output current, and operates on
a single 5V power supply. It is available
in 8-pm plastic DIPs or SOICs.
For further information circle 275 on
StJE^Pn service coupon or contact
atek, PO Box 397, West Ryde 2114-
phone (02) 874 0122.
Quad op-amp has
450MHz bandwidth
Burr-Brown’s new OPA4658 is a quad
ultra-wideband, low power current feed¬
back operational amplifier featuring a
high slew rate and low differential
gain/phase errors. Its low 50mW power
dissipation combines with a high
bandwidth of 450MHz in a gain of two
to make the OPA4658 a perfect low cost
choice for medical imaging, high resol u-
tion video, communications, pulse
amplifiers, and high speed signal
processing applications.
For further information circle 276 on
the reader service coupon or contact
Kene |e c ( 2 Apollo Court, Blackburn
3130, phone Toll Free (008) 335 245.
WANTED
SCRAP PCB’s
We will pay CASH for your
scrap/obsolete PCB’s
containing soldered/socketted
DRAM, EPROMs or CPUs
SURPLUS
STOCK
all semicon’s considered
Memory International
Voice: (61 2) 452 6100 1
Fax: (61 2) 452 6102
jt
oj
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CC
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Test & Measuring Instruments Feature:
FLUKE'S ENHANCED ,,
'SERIES II' SCOPEMETERS
eluding a full built-in ‘online help’ facility.
by JIM ROWE
When Philips/Fluke released the
ScopeMeter range of handheld multi¬
function instruments in 1991, they
created a lot of interest. Combining a
3000-count true-RMS DMM with a
50MHz bandwidth DSO and frequen¬
cy counter in a compact and rugge
form, the new instruments represented
an important step forward in terms of
the tools available for field servicing
and maintenance.
The original ScopeMeter models won a
number of industry awards, and have
been very successful. Their success in
fact encouraged other T&M makers to
develop similar multifunction portable in¬
struments, such as the Tektronix
THM565 TekMeter reviewed in our May
1994 issue.
But recently the ScopeMeter range it¬
self has been expanded and enhanced,
with the addition of four new ‘Series II
models: the models 91 and 92, the model
96 and the model 99. The new models
offer additional features and facilities,
which should make them of even more
value for measurements ‘in the field .
Among the measurement functions
provided by the new instruments is a
‘Measure Menu’ facility, which allows
the user to select easily any of 30 dif¬
ferent measurement tasks. Upon selec¬
tion of any desired task, the instrument
automatically configures itself to make
the measurement.
Another feature is a selectable Con¬
tinuous Autoset’ function, which as the
name suggests allows the instrument to
continuously ‘track’ the signal being
measured, and dynamically adjusts the
instrument’s range and mode settings to
optimise measurements or signal display.
Further features of the new models in¬
clude a windowing on-screen menu sys¬
tem for manual mode, range and function
112 ELECTRONICS Australia, June 1995
selection, to make the instruments much
easier and more convenient to ‘drive .
Like many modem bench DSO’s the new
ScopeMeters also allow continuous
measurement and indication of many sig¬
nal parameters while in scope mode,
reducing the need to switch back to
DMM/counter modes.
In any case the signal waveform is also
displayed in meter mode, so that the two
modes overlap in function a lot more than
before.
There’s also a pair of ‘Min/Max’ func¬
tions on the new models, one of which
allows you to see the maximum and min¬
imum values of a varying signal. The
other allows you to graph the maximum,
minimum and average values of a signal
over a period of time — which can be
anywhere between two minutes and 30
days. Very handy for spotting problems
due to cyclic events!
One of the nicest features in the new
models, though, is an inbuilt ‘on line
help’ facility, which provides context-
sensitive help information at any time —
in much the same way as most PC
software running under Windows. In this
case all you have to do, if you re unsure
of the correct procedure at any stage, is
press the ScopeMeter’s T button, and
the appropriate help information appears
on the screen. This is an excellent system
in a portable instrument, as you general¬
ly won’t have the user manual accessible
to you out in the field...
The new model 96 and 99 Scope¬
Meters also feature large, non-volatile in¬
ternal memories, for storing screen
images, instrument setups and measure¬
ment waveforms/data. The waveform and
parameters of a reference or ‘bogie’ sig¬
nal can also be stored in memory, for
comparison with a signal in the equip¬
ment being tested. The stored wave¬
forms/data can be recalled at any time, or
sent to a printer. In the case of the model
99 the data can also be downloaded to a
PC for further analysis or permanent
storage. The model 96 can store 20
setups, 10 signal waveforms with setting
data, and up to five screen images; with
the model 99 these figures increase to 40,
20 and 10 respectively.
Like the existing Scopemeters, the
Series II models use an 84mm square
super twisted’ LCD display, with a
resolution of 240 x 240 pixels and user-
selected electroluminescent backlighting.
They operate from an internal 4.8V
NiCad battery pack, which typically runs
the instrument for about four hours after
charging from the mains via the supplied
charger. Charging takes about 16 hours
for a fully flattened battery.
Rated frequency response of the
ScopeMeters in scope mode is from DC
to 50MHz (-3dB), with a maximum sam¬
pling rate of 25MS/s and a resolution of
eight bits. Input impedance is a standard
1 M/25pF, or 10M/13pF with the 101
divider probes. All models except the 91
have dual input channels.
The horizontal sweep range is from
1 Ons/div to ls/div, with a choice of three
modes: recurrent, single shot and roll.
Record length is either 256 or 512
samples (10 or 20 divisions). There’s a
comprehensive range of trigger facilities,
and in the case of the models 96 and 99 a
wide range of cursor-driven waveform
parameter measurements. The model 99
also provides ‘waveform maths’ func¬
tions including add, subtract, multiply, in¬
vert, filtering or integration of the input
signals. With the use of optional current
probes, it can calculate instantaneous or
mean (real) power.
A very useful feature of the instruments
in scope mode is the ability to detect and
indicate glitches of less than 40ns dura¬
tion, at sweep speeds of 1 us/div or slower
in input A.
Another nice feature is the ‘analog like’
grey-scale display, which gives a good
simulation of the way fast and short-lived
phenomena are displayed less brightly on
a conventional analog scope.
In meter mode, the instruments pro¬
vide eight basic DC voltage ranges
from lOOmV to 300V FS, with measure¬
ments to 3kV possible using a 10:1
probe. Basic accuracy is +/-(0.5% + 5
counts). A similar set of ranges is avail¬
able for AC or (AC + DC) true-RMS
measurement, except that here the top
range only extends to 250V
FS. Rated accuracy is +/-(1 % +
10 counts) at 50/60Hz, or +/-
(2% + 15 counts) between
20Hz and 20kHz. This further
discounts to +/- (3% + 20
counts) between 5Hz and
1MHz.
There are seven resistance
ranges, with FS readings rang¬
ing from 30ft to 30Mft. Rated
accuracy on all but the lowest
range is +/-(0.5% + 5 counts),
and +/-(2.5% + 25 counts) on
the 30ft range.
03,50 Vrms AC
■*"02,23 V DC
AUTO
ut input : A '
HZ IprOBE 10: 1 1
r
r
RANGE:
+ 10V
— —- -os*
Sens
SCOPE SUES Q -H-
-10V
02253
EXTmV
Above: A typical screen when the
ScopeMeter is used in meter ' mode.
Below: A screen in scope' mode.
3 1 n 2VD n V 1 S 2V0FF 10 :1
lOms^OIV Trjg:AT-2DIV
Cursor readings on waveform
FREQUENCY RISE TIME
34.2 Hz 1Q0, S
HOFF asioaiai zero
bLOPE SINGLE
Frequency measurements are possible
between 1Hz and 5MHz, with four digits
of resolution and a rated accuracy of +/-
(0.5% + 2 counts). Also provided is the
ability to measure RPM, duty cycle, pulse
width, dBV, dBm, dBW or audio/RF
watts, apart from the usual diode test
range.
In addition to the features already
mentioned, the new model 99 Scope-
Meter also includes an inbuilt spot-fre¬
quency LF signal generator, capable of
providing either a IV p-p sinewave at
976Hz, or a 5V p-p square wave of either
488, 976 or 1950Hz. In each case the out¬
put impedance is 400ft, and the sinewave
output has a rated distortion of less than
3% (THD).
A close up view of the main input connectors, at the top
of the ScopeMeter. The meter jacks are in the centre with
the scope inputs on either side.
Like the model 96, the model 99 has
provision for an optically isolated RS-
232C interface cable, via a small connec¬
tor moulded into the right hand side of
the case. However with the 99 this inter¬
face can be used not just for dumping
screens and measurements to a serial
printer (Epson FX/LQ, HP ThinkJet or
LaserJet), but also for linking the Scope-
Meter to a PC. This allows the 99 to
upload and download measurement set¬
ups, or download waveforms and meas¬
urements for further analysis, storage or
data logging.
Trying one out
We were very kindly loaned a Scope-
Meter 99 to try out on your behalf, by
Sydney’s Fluke/Philips T&M distributor
Obiat. As expected it gave a very good
account of itself, and we found it a
pleasure to use.
Although not exactly pocket sized — it
measures 260 x 130 x 60mm, and weighs
1.5kg — there's no denying that it still
delivers a great deal of measurement
horsepower in a convenient and relatively
compact package.
In terms of operation, we particularly
liked the ‘Auto Set’ button, which like
that on many modem DSO’s gives you a
stable and optimised (or very nearly so)
display of just about any signal, with a
single key press. We also liked the built-
in online help system, and its ability to
provide context sensitive help informa¬
tion at virtually any time — and again
with a single key press.
Apart from these special points, we
also liked the way the new ScopeMeter
is operated via a friendly system of
menus, and the way it provides greater
functional overlap between the scope
and meter modes, to reduce the need
tor mode switching. In general it seems
notably more convenient to use than the
earlier models.
The performance was checked out,
and generally either met or comfortab¬
ly exceeded the quoted specs. For ex¬
ample the upper frequency response of
both vertical scope channels
measured -3dB at around
68MHz, well above the quoted
50MHz, with a fairly smooth
rolloff and very little
evidence of aliasing.
Obiat sent one of the optional
optically isolated serial inter¬
laces and its matching
software, so we could try out
this facility as well. However
either we were doing some¬
thing wrong, or the sample in¬
terface and/or its software were
faulty, because we couldn't get
ELECTRONICS Australia, June 1995 113
READER INFO NO. 27
flukes series ir scopemeters
MILLIGUASS
Quality Magnetic ^
1 Field Meters
Accuracy and Reliability
at a reasonable cost.
• CONTACT •
;radshield
AUSTRALIA PTY LTD
Toll Free 1 800 641 118
FAX (07 5) 711 3<IB 4
CD
CM |
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UNIVERSITY
RESOURCES
AVAILABLE.
Get access to highly trained
microelectronic engineering
students and the extensive
electronic resources of Griffith
University.
The Industrial Affiliates
Programme, an Australian first,
I makes final year students
available to organisations for 3
months. Students get involved
industry projects at the
conceptual stage through to
the completion of prototypes.
The next programme starts
again in March 1996.
To tap these resources,
contact Carol-joy Patrick now
on phone (07) 875 5007 or fax
(07) 875 6726.
G R IFF] T H
UNIVERSITY
WHAT'S AN
OC32DIO?
Ocean Controls have released their
OC32DIO card. Connect it to a computer
using the RS232 serial port or RS485 port
for easy data input and control.
Features include:
• Multi drop connection using Modbus protocol;
• 16 digital outputs OC type;
• 16 digital inputs;
• 8 of the digital inputs operate as low speed
counters;
• 1 high speed counter;
• Battery backed memory and screw terminals
for easy connection.
But There's More. No Not Steak Knives!
The OC32DIO card can work in back to back
systems. An OC32DIO can be easily programmed
to be a master with up to 4 other OC32DIO cards
being slaves. This allows you to control devices
at 5 different locations up to IKm apart. At $225
each they're an economical solution.
For more information contact:
OCEAN CONTROLS
4 Ferguson Drive, Balnarring, Vic. 3926
TEL: (059) 831 163 or 015 837 646
A close up view showing the side of the ScopeMeter, and the opt'cally 'solated
seriafinterface connector. Also shown is the matching cable connector, on the
top, while the round hole below is the socket for the power input lead.
the PC to ‘find’ the ScopeMeter via the
designated serial port. Apart from this
minor glitch, though, we found the
ScopeMeter 99 a most impressive instru¬
ment indeed.
For those who would otherwise need
to lug around a dual-trace 50MHz scope
and DMM for performing field measure¬
ments, it should be an attractive proposi¬
tion. And coming from Philips/Fluke,
there’s an impressively wide range of op¬
tional probes, adaptors and other well
made accessories.
The quoted price of the Series II Model
99 is $3650, with the model 96, 92 and
91 priced at $3190, $2650 and $1980
respectively. Further information on both
these and the original ScopeMeter
models is available from Obiat, of 129
Queen Street (PO Box 37), Beaconsfield
2015; phone (02) 698 4776, or fax (02)
699 9170. ❖
Want to get more
in-depth with the 'how 1 , 'why 1
and 'where' in the world of
music, recording, multimedia
and more? Read
AUSTRALIA^^^ _
DIGhXCxL.
MUSIC • RECORDING • MULTIMEDIA
On sale at your newsagent
or phone toll free 008 800 933
NEW FIELD STRENGTH METER APM 745 SAT
Reception range 47 - 205D MHz includes Satellite and MMDS
Level measuring range 2D - 13D dDjuV
Microprocessor-controlled keyboard
33 program storages with station identification
Teletext, printer [optional], RS-232 C-interface
With spectrum analyzer, zoom, Line blanking interval B analog level
indication and reference tone
Professional multinorm field strength meter for worldwide application
iccfS r— ji
ELEZdH-RCZlMIC:
i
Skandia
READER INFO NO. 28
SKANDIA ELECTRONICS PTY. LTD.
HEAD OFFICE: 183 BURWOOD ROAD,
(PO BOX 488) HAWTHORN, VIC. 3122
TEL: (03) 9819 2466 FAX: (03) 9819 4281
SYDNEY OFFICE: SUITE 12, 354-356
CHURCH STREET, PARRAMATTA, NSW 2150
TEL: (02) 630 0888 FAX: (02) 630 8690
SOLE AUSTRALASIAN DISTRIBUTORS FOR KONIG ELECTRONIC OF GERMANY.
Test & Measuring Instruments Feature:
HP’s new 54620A
Logic Analyser
Latest addition to the Hewlett-Packard 54600 series of lower-priced test instruments is the 54620A
Logic Analyser, designed to be as easy to drive as a scope. It also offers 16 input channels, a maxi¬
mum sampling speed of 500MS/S, sweep speeds up to 5ns/div and glitch capture of pulses as nar¬
row as 3.5ns — plus the ability to be interfaced easily with a PC.
by JIM ROWE
When Hewlett-Packard released its
54600-Series of lower priced DSOs in
early 1991, they caused quite an
upheaval in the T&M market. Not only
were the new instruments notably
cheaper than existing instruments of
comparable performance, but they were
more compact, lighter in weight and
also significantly easier to use. Perhaps
even more impressive was the way they
combined the fast display
updating speed and ‘feel’
of an analog scope with
the added functions of a
modem DSO, in a seam¬
less and transparent way.
After trying out the
new 54620A for a few
weeks, I suspect that HP
has just pulled off a
similar and just as sig¬
nificant coup in the realm
of logic analysers.
The 54620A is built in
virtually the same case as
the 54600 series of
scopes, and is clearly a
‘close relative'. Not
surprisingly it seems to
be made in the same
Colorado Springs
division responsible for
the scopes, and even
takes many of the same
optional add-ons — like the 54650A
HP-IB Interface Module, the 54652A
Parallel Interface Module and the
54651A RS-232C Interface Module
(used to link it with a PC). It also mates
with HP's Benchlink for Windows
software, developed for easy com¬
munication between a PC and the 54600
series scopes.
Just as HP’s engineers and marketing
people did a lot of customer research
before designing the scopes, to find out
what users really wanted, they seem to
have done a similar exercise with the
54620A. Which makes a great deal of
sense, of course, because this type of re¬
search obviously paid off the first time.
I guess it doesn’t come as any surprise
to learn that they found much the same
situation with logic analysers as they’d
found previously with DSO’s — name¬
ly, that many engineers and technicians
find the traditional instruments just too
complicated to drive, and often rather
‘user unfriendly’ into the bargain.
When they asked what users would
like in a logic analyser, they generally
got a fairly straightforward answer:
‘Just make it as easy to drive as a
scope!’ So that’s exactly what they set
out to do, in developing the 54620A.
To my mind they’ve succeeded ad¬
mirably. Like the 546(X) series of
scopes the new analyser is surpris¬
ingly straightforward to use, with rela¬
tively few controls and much of the
same ‘intuitive’ feel that is evident
with its scope siblings. In fact many of
the controls are virtually the same,
like the horizontal timebase and delay
controls, and the mode and general
setup controls.
As with the scopes,
many of the analyser
functions are set up using
a series of on-screen
menues, in conjunction
with either the front-panel
controls or six ‘software
configured’ buttons along
the bottom of the display
screen itself. And even
more like the scopes, it
also has one of those great
‘Autoscale’ buttons, to
perform a complete auto¬
matic setup with a single
keypress.
Obviously Autoscale
can’t read your mind and
set up the triggering to
capture the exact logic
event you’re interested in,
but a lot of the time it will
at least get you quickly
into the basic signal
‘ballpark’ where the event is likely
to be. Which is a big step forward,
compared with many traditional logic
analysers.
(Incidentally, Autoscale also scans the
inputs to detect which ones seem
‘active’, and automatically limits the
display to these alone for optimum
clarity. Of course you can very easily
override it and reinstate the other inputs,
if you wish.)
116
ELECTRONICS Australia, June 1995
Another nice feature is that the
54620A allows you to apply a six-
character ‘label’ to each channel, to im¬
prove the ease of reading the screen
display and any printed screen dumps.
The labels are added via an easy-to-
drive front panel facility, which has a
‘library’ of handy labels built in, to
speed things up. You only have as¬
semble the really unusual ones yourself,
one character at a time...
Analyser performance
In terms of its logic analysis
capabilities, the 54620A
is a 16-channel instru¬
ment. The main input
channels are grouped in
two sets of eight, num¬
bered 0-15, and are
brought out to a 40-way
DIL connector at the
lower right comer of the
front panel. A matching
cable assembly plugs
into this connector, and
brings each group of
eight inputs out via a
special woven ribbon
cable to a ‘probe head’
fitted with eight flying
signal leads — each en¬
ding in a numbered pin¬
jack — and a matching
earth pinjack. Also sup¬
plied is a set of micro
spring clips, which mate
with the pinjacks to
allow connections to
device pins.
All of these main in¬
puts are of quite high
impedance (100k/8pF),
and can be programmed
for preset threshold
levels corresponding to
TTL, CMOS or ECL
logic levels. Rated channel to chan¬
nel timing skew is typically 2ns, and
3.0ns maximum.
As well as the 16 basic input chan¬
nels, there’s also an ‘External Trigger’
input via a front panel BNC connector.
This input has an input impedance of
lM/12pF, has an independently adjus¬
table threshold level and is suitable for
use with standard probes such as the
HP 1007X.
The maximum sample rate of the
54620A is 500MS/s, giving it a mini¬
mum timing resolution of 2ns. The
range of sweep speeds is from ls/div up
to 5ns/div, with both a main and delayed
timebase system. It takes 2K samples
per record at sampling periods of 8ns
and slower (i.e., sweep speeds of
lus/div to ls/div), and 8K samples per
record at the two fastest sampling
periods of 2ns and 4ns (sweep speeds of
5ns/div to 500ns/div).
Basic timebase accuracy is 0.01%,
and the cursor measurement accuracy
for a single-channel timing measure¬
ment is +/-(Sample period + 0.01% of
reading) +/-0.2% of screen width. This
is degraded by the channel to channel
skew, for channel to channel timing
measurements, and by a delay jitter of
lOppm in delayed timebase mode.
As this is a logic analyser rather than
Extracted from the Hewlett-Packard manual , this diagram
indicates most of the front panel controls and connections of the
54620A logic analyser — plus the input cable assembly.
a scope, the delaying system allows
both negative (pre-trigger) or positive
(post-trigger) sweep delay. The maxi¬
mum delay is independent of the time
reference, which can be in the centre,
left or right of the display.
For the two shortest sampling periods
the maximum pre-trigger delay is 8077
times the sample period, and 2019 times
for the longer sampling periods. For
post-trigger delaying the maximum
delay for sampling periods of 2ns to 8ns
is 8.839ms, and for the longer sampling
periods 1,048,575 times the sampling
period or 100s, whichever is larger.
In general the delayed sweep can be
from twice to 200 million times the
main sweep setting, up to a minimum
period of 5ns/div, but it must always be
at least twice the main sweep speed. The
minimum display update rate is 10 full
screens per second, regardless of the
number of channels being displayed —
but assuming no parameter measure¬
ments are being taken.
The ‘glitch detect and capture’ mode
is activated automatically at all sweep
speeds where the sampling period is
greater than 4ns (lus/div and slower),
and captures pulses as narrow as 3.5ns.
The maximum glitch width is Ins less
than the current sample period.
Needless to say once a set of samples
has been captured, you can
pan along the waveforms in
memory, and ‘zoom in’ to
examine any particular
event of interest.
As you might expect
from a logic analyser, the
triggering system is par¬
ticularly flexible. In general
it can be set to trigger from
a very wide range of
events, based on the 16
main inputs and the Ext
Trigger input. The event
can be a logic transition
‘edge’ on any one of these
inputs; a pattern of highs,
lows or ‘don’t cares’ on any
desired combination of in¬
puts; an AND combination
of an edge on one channel,
and a pattern; or n\’o such
‘edge AND pattern’ events,
combined with a choice of
operators including AND,
OR, Then, Entered, Exited,
Duration longer than. Dura¬
tion shorter than, and Oc¬
curs N times.
The rated minimum setup
time for a pattern, prior to
an edge being combined
with it for AND triggering,
plus the channel-to-channel
is 3ns
skew. Similarly the minimum pattern
hold time, for the same type of trigger¬
ing, is 5ns plus the skew. The minimum
detectable pattern width is 13ns plus the
skew at sweep speeds of 5ns/div to
lus/div; at speeds of 2us/div and slower
it becomes (Ins + 1 sample period +
skew + 0.01%).
By the way, the 54620A also provides
a Trigger Out signal, which delivers a
rising edge at the detected trigger point
— for triggering a scope or other instru¬
ment. The Trigger Out signal edge is
delayed by approximately 85ns from the
trigger event, with a jitter of +/-(sample
period + lOppm). The output is via a
second front panel BNC connector, and
can deliver a peak to peak output of
ELECTRONICS Australia, June 1995
117
Not
your
average
disability.
Multiple sclerosis
usually first affects
people in their
twenties and
thirties. Its
symptoms are
unpredictable,
sometimes causing
severe disability.
Thankfully the
problems are more
often only mild to
moderate.
Most people with
MS are very
independent With
your understanding
they usually stay
that way.
MS
For more information about
multiple sclerosis contact
the MS Society in your state.
HP’S 54620A LOGIC ANALYSER
Also taken from the Hewlett-Packard manual, this diagram gives a representation
of the analyser’s screen display , with many of its features identified. Each of the
active channel traces can easily be given an identification label.
more than 2V into 50Q, or 4.8V into an
open circuit.
As with the 54600 series scopes, the
analyser’s display is via a raster image
on a 166mm-diagonal (nominal 7")
CRT with fast response green phos¬
phor. The display resolution is 256
vertical by 500 horizontal pixels, with
a user-selectable software generated 8
x 10 grid graticule. The Autostore
function allows previously stored
sweeps to be displayed at half intensity,
giving an ‘analog’ look and making it
easy to distinguish between new and
‘historic’ waveform data.
Standard measurement functions
available on the 54620A for the signal
on any selected input channel are
similar to the timing measurements
available on the scopes: Frequency,
Period, +Width, -Width and Duty Cycle.
For two-channel relative measurements
there’s Channel-to-Channel Delay, Hold
Time and Setup Time. Many other
measurements are possible by using the
54620A’s two measurement cursors, and
the measurement system automatically
tracks changes in the horizontal sweep
rate and delay controls.
Trying it out
Hewlett-Packard Australia very
kindly made a sample 54600A Logic
Analyser available for a while, allow¬
ing us to get a good ‘feel’ for both its
performance and ease of use. We were
certainly most impressed with the in¬
strument, in both respects.
Along with the basic analyser and its
input cables, etc., they also provided an
HP 54654A ‘Self-Paced Training Kit’,
designed to help users get familiar with
the controls and use of both the 54620A
and its sibling scopes.
The kit consists of a battery-powered
PCB module, which generates quite a
large number of carefully-chosen test
signals, plus a Training Guide manual
which takes you through the familiarisa¬
tion process.
Before we used the 54620A for any¬
thing else, then, we worked through the
section of the Training Guide dealing
with it, and can report that this provides
a very effective way to get yourself
familiar with the instrument.
We also used the 54620A to explore
around inside a typical PC, to get a fur¬
ther idea of its ease of use. Here again
we were pleasantly surprised, and found
it notably more ‘friendly’ than previous
logic analysers we’ve tried.
On the whole, then, I believe that with
the 54620A Hewlett-Packard has indeed
achieved a very welcome breakthrough
in logic analyser design. While retaining
plenty of performance and functionality,
they’ve come up with an instrument that
is much easier and more intuitive to use
than traditional instruments have been.
And an instrument that’s easier to drive
is always going to be more useful in
practice than one that isn’t, surely.
The quoted price for the 54620A
Logic Analyser is $4565 plus tax, with a
further $306 plus tax for the optional
54654A Self-Paced Training Kit.
Further information on these products
is available by calling the HP Customer
Service Centre on 13 1347. ❖
118
ELECTRONICS Australia, June 1995
Special Feature:
The latest test and
measuring instruments
Graphical multimeter
with 0.025% accuracy
Fluke has introduced its new 860
series of graphical multimeters (GMM),
a new category of test instrument that
combine multimeter functions with a
waveform display and other functions.
There are three instruments in the 860
series. Key features of all three include
meter mode, waveform display, data log¬
ging with graphical readout, in-circuit
component testing and logic test mode.
The meter mode has up to 0.025% ac¬
curacy, 4.5-digit resolution, a dual digital
display that gives information about the
parameter being measured and an analog
bargraph. Measurement functions in¬
clude current, resistance, conductance,
capacitance, frequency, duty cycle, pulse
width, period, dB and voltage.
The waveform display has a
bandwidth of 1MHz, and enhances the
numeric display by providing more in¬
formation about the parameter being
measured. In graphing mode, the instru¬
ment plots readings for up to 30 hours, at
intervals from one second to 15 minutes.
The in-circuit test allows signatures of
in-circuit components to be obtained for
troubleshooting purposes. These signa¬
tures are then compared to those of a
known good circuit. The logic test indi¬
cates logic transitions to 10MHz, shows
logic levels, the frequency of activity
and the average DC voltage. The model
863 is priced at $795, model 865 is $995
and the 867 is $1295.
For further information, circle 202 on
the reader service coupon or contact
Philips Scientific and Industrial, 34
Waterloo Road, North Ryde 2113; phone
(02) 888 8222.
Multimeter and clamp
meter range from Europe
The European based Carlo Gavazzi
group has released a range of digital
multimeters and clamp meters, under the
Pantec brand. The multimeters feature
arched bargraphs with up to 65 segments
and up to 4000 counts.
Other features include true RMS volt¬
age and current ranges, capacitance
functions, min/max recording, data
hold and data delay modes,
auto/manual ranging, ovrload protec¬
tion, memory store and recall func¬
tions, diode test and auto power off.
Each meter comes with test leads,
holster, battery and operator manual.
The clamp meters feature safety
design to IEC 348, true RMS voltage
and current ranges, DC current to
Portable DSO plus true RMS DMM
The PalmScope 320 from Escort Instruments combines four
full function test instruments.
These are a two channel 20MHz digital storage scope, a 3-
3/4 digit true RMS digital mulimeter (with AC/DC current, a
seven digit 20MHz frequency period counter, and an eight
channel, 20MHz logic analyser.
Specifications include: 2k (1920 point) deep DSO
memory; full AC V, DC V, AC A, DC A and ohms functions;
a 7-digit frequency counter with a lOppm basic accuracy;
and an eight channel logic analyser with both timing and
state signal displays.
The instrument is supplied with oscilloscope and multimeter
probes, protective rubber holster, AC power pack, NiCad
rechargeable battery pack and slim briefcase style carrying
case. Options include RS-232 interface cable, PC data transfer
software and logic analyser probes.
For further information circle 201 on the reader service
coupon or contact Emona Instruments, 86 Parramatta Road,
Camperdown 2050; phone (02) 519 3933.
ELECTRONICS Australia, June 1995
119
READER INFO NO. 29
PalmScope 320
Full Featured
Instruments in Your Hand
Escort Instruments' PalmScope is the latest
generation in portable, integrated test instrument
packages. It combines four full function test
instruments with specifications normally only
found on dedicated bench-top instruments.
DSO
DMM
♦ 20MHz, 20MS/s
♦ 2 Channels
♦ Cursors, Auto set-Up
♦ 20 Display Memories
♦ 4000 Count, Bar Graph
♦ AC/DC V & A, R, Diode
♦ Autoranging
♦ True RMS
Counter ■■■
♦ 7 Digits
♦ 20MHz Range
♦ 0.001% Accuracy
♦ Period Measurement
Logic Analyser mm
♦ 8 Channels
♦ 20MHz Clock
♦ Timing/State Display
♦ TTL/CMOS Trigger Levels
The Complete Package ummmmmmmmmmmm
The Escort Palmscope 320 features backlit hi-res LCD
display, and RS-232 and printer interfaces as standard. It is
supplied complete with scope and DMM probes, protective
ruDoer holster, AC power pack, Ni-Cad rechargeable
battery pack and slim briefcase style carry case.
EMONfV
INSTRUMENTS
NSW (02)519 3933
VIC (03) v 889 0427
QLD (07) <367 1744
WA (09) 361 4200
Distributors in all States
TEST AND MEASURING INSTRUMENTS
1000A, DC voltage ranges, resistance ranges, continuity test,
frequency to 4MHz, data hold, auto and manual ranging and
max/min recording.
For further information circle 203 on the reader service
coupon or contact Obiat, 129 Queen Street, Beaconsfield 2015;
phone (02) 698 4111.
Intelligent Megger
The new intelligent AVO Megger IPAT14 (for 240V rated
appliances) and 1PAT15 (for 110V and 240V rated appliances)
perform a range of electrical and electronic appliance tests in¬
cluding earth continuity, bond, insulation, operation, earth
leakage, flash (IPAT15 only), lead and extension lead tests.
They are suitable for periodic safety tests of appliances used by
factories, equipment renting companies, hospitals, manufac¬
turers and so on.
The testers can be supplied with an optional barcode reader
and barcode label printer for positive identification of tested
appliances. Testing programs are menu selected, and the
operator can also use the detachable QWERTY keyboard to
enter visual inspection details of appliances. Complete test
records are stored in the IPAT14/15 memory with 6000 test
result capacity. This data can be output to the integral 3-1/2"
floppy disk drive, or via the RS-232 port to external printers or
host computer.
The IPAT software supplied with the instruments has features
that allow user defined pass/fail limits and an asset manage¬
ment feature to indicate ‘due for test’ reports.
Test results can be viewed on the large, back lit LCD screen
and printed via the RS-232 port. Test sequences and results are
indicated on the display along with user prompting messages.
For further information circle 204 on the reader service
coupon or contact Nilsen Technologies, 150 Oxford Street,
Collingwood 3066; phone (03) 419 9999.
Oscillograph records
at 250mm/sec
The latest oscillograph recorder from
test and measurement specialist
Yokogawa offers high definition, real
time recording up to 250mm/sec with
large, 256K sample/channel data
memories and a 3.5" floppy disk drive,
all packed into a compact body with an
A4 footprint.
Yokogawa’s OR 1400 is a fast eight
channel universal oscillographic re¬
corder designed to be easy to use
through its natueal language displays,
plug-in input modules for flexible signal
handling, arithmetic and statistical com¬
puting capabilities, and versatile mixed
analog/digital recording features.
The OR14(X) input architecture allows
high voltage and universal (volt¬
age/thermocouple) plug-ins to be mixed
freely all across all eight channels, to
handle signals from thermocouple levels
up to 240V AC. The high voltage
modules features wide range zero sup¬
pression capability.
Range and zero position set up have
been designed to have an analog feel, in
that they can be set with a rotary knob
while viewing an image of the recording
trace on the graphic display..
The OR 14(X)’s ability to provide clean,
clear recordings even at chart speeds up
to 250mm/sec is achieved to Yokogawa’s
innovative dot overlap technology. This
eliminates the stepped appearance nor¬
mally associated with digital based ther¬
mal recording.
The built-in 3.5" floppy disk drive per¬
mits acquired data to be saved for further
analysis on a PC using Yokogawa’s ac¬
cessory software packages.
For further information circle 204
on the reader service card or contact
Yokogawa Australia, 25 - 27 Paul Street
North, North Ryde 2113; phone (02)
805 0699.
FS meter covers
satellite & MMDS
Skandia Electronics has released the
Konig APM-380 Field Strength Meter,
which is currently being used with great
success by installers of Galaxy Pay TV.
The APM-380 is capable of measuring
signal levels for satellite, terrestrial and
MMDS transmissions
The instrument has been developed
to supply the required operating volt¬
age to the MMDS down converter, as
well as powering the satellite LNBF.
This feature eliminates the need for addi¬
tional power supplies for the MMDS
downconverter, thus allowing easy
measurements to be taken direct from
the downconverter.
The satellite meter function allows for
individual tuning of transponders, while
a satellite finder feature faciltates a broad
banded sweep of 950 to 2050MHz,
which makes satellite location easy. The
battery supply allows up to 2.5 hours
continual operation of the downcon¬
verter. Rechargeable batteries and bat¬
tery charger, as well as a protective case
are supplied with each unit.
A new feature of this model is auto-
correction, which eliminates tedious ad¬
ditional calculations and correction
curve drop out.
For further information circle 240
on the reader service coupon or con¬
tact Skandia Electronics, 183 Bur-
wood Road, Hawthorn 3122; phone (09)
9819 2466.
QUALITY AT
AFFORDABLE
S
DIGITAL MULTIMETER
DMM1050
• 3.5 Digit LCD display
• Instantaneous readout
• AC/DC current
to 10 Amps
• 26 Ranges
• Continuity'
buzzer
• Diode check &
measurement
• Handy flip up stand
• Input impedance 10 MO
• Side slots for test leads hands-free operation
and storage
• 12 month guarantee
ANALOGUE MULTIMETER
POCKET SIZE
MM202
• Ideal for trades, home
and automotive use
• Input Impedance:
DC 2k ohm/volt
• Jewelled meter
movement, moving
coil type
• Handy pocket size
16 ranges, selected
by single switch
ANALOGUE MULTIMETER
MM308
• Ideal for engineers,
service technicians
and trades people
• Input impedance:
DC 20k ohm/volt,
AC 9k ohm/volt
• Jewelled meter
movement,
moving coil
type
• Large scale for
easy reading
• Continuity beeper
• 20 ranges, selected by single switch
Available from selected electrical component
retailers and major automotive stores.
QUALITY PRODUCTS
RESPONSE 7998
ELECTRONICS Australia, June 1995 121
READER INFO NO. 30
READER INFO NO. 31
TEST AND MEASURING INSTRUMENTS
Improved Hameg
30MHz oscilloscope
The new Hameg model HM303 oscil¬
loscope supersedes the HM203, of which
over 170,000 were sold world wide. The
bandwidth has been extended from
20MHz to 30MHz, while the top sweep
rate has been increased to lOns/div. The
HM303 is therefore very suitable for
waveform display in the DC to 70MHz
frequency range.
The HM303 offers a special fast rise
time lkHz/lMHz calibrator, permitting
high quality probe compensation across
the entire frequency range. An overscan
indicator assists in vertical display
amplitude and position adjustments.
The instrument is capable of triggering
on input waveforms over 100MHz and
on signal levels as small as half a
division. An active video sync-separator
permits detailed examination of complex
TV signal inputs. The use of a switching
power supply minimises both weight and
power consumption, and the CRT is fully
mu-metal shielded against outside mag¬
netic fields.
The HM303 is supplied standard with
an inbuilt component tester, operator’s
manual and two probes (1:1/10:1). Op¬
tional accessories include a viewing
hood and carrying case.
For further information circle 205 on
the reader service card or contact
Kenelec, 2 Apollo Court, Blackburn
3130; phone toll free (008) 335 245.
ISDN tester
Trend Communications has announced
the Aurora Duet, an ISDN basic rate
tester. The new unit has a totally new ar¬
chitecture but its features complement
those of other units in the Aurora range.
The instrument is a second generation
ISDN tester, developed to locate and
solve specialist problems related to ad¬
vanced ISDN networks. Its key features
include a built-in monitor and decode
facility, a choice of three optional U in¬
terfaces (2B1Q, 4B3T and UpO) with
the ability for all three to be co-resident.
The unit can power a network termina¬
tion device for the UpO U interface
E = mC !
.a c
HI-TECH C
for embedded systems.
The world's best C cross compilers.
Available for most popular chips.
HI-TECH Software
Ph. (07) 300 5011
Fax (07) 300 5246
PO Box 103 ALDERLEY
QLD 4051.
3 3:33 PM
Fri. Feb 10. 1995
Protel Del
■ii™ Edit
Library
Netlist Auto
Current Qp
New
.IUI:sl- i
■!: + ! ; -li
Open-
Close
Restore Backup
Save
Save As...
Save Copy As...
Save A|l
Protel Technology
Technopark Dowsings Point 7010 Tasmania
Protel Design
System
for Windows
I Schematic Entry
I PCB Design
I Autorouting
I Autoplace
I Simulation interfaces
I FPGA and EPLD
support
Technology
technology
For more information phone
Toll Free
1800 030 949
122
ELECTRONICS Australia. June 1995
READER INFO NO. 32
and the S interface, and has storage for up to eight dif¬
ferent protocols. Software upgrades of the instrument can be
downloaded directly and new protocols added via the use of
flash memory.
The tester’s monitor facility enables it to extract information i
from a PBX/network line and capture it into memory for
review at a later stage.
For further information contact Trend Communications,
Knaves Beech Estate, Loudwater, High Wycombe, Bucks
HP10 P9QX, UK; phone (44 628 524 977).
Instrument for EMC testing
Electromagnetic immunity testing to European standards be¬
comes mandatory in Europe in January 1996, and in many
other countries including Australia very soon thereafter.
Manufacturers of all electrical and electronic equipment from
household goods to laboratory equipment will have to perform
fast transient and burst voltage EMC tests.
The NSG 2025 family of fast transient and burst interference
generators from Schaffner meet all the requirements of the
European norms EN50082-1, -2, international standard IEC
1000-4-4 and US requirements ANS1-1EEE C.62.41. Standard
test pulses are pre-programmed, custom pulse generation and
test management capabilities for detailed design verification
and pre-compliance testing.
The NSG 2025 hardware is based on a configurable, modular
‘building block’ concept which allows users to select pulse
generator, one or three phase coupling network, manual and
software control elements and UUT (unit under test) connec¬
tions, to configure an EMC test station to suit the application.
Options include a pulse generator with maximum burst
amplitudes of 4.4kV or 8kV and network current of 16A or
30A. A maximum burst frequency of 1MHz in the 4.4kV ver¬
sion facilitates detailed product analysis, and offers a generous
margin for future modification of world standards.
Instrument control is via a PC Windows based software
package WIN 2025, or from a front panel key-pad and display.
The software control package provides built-in IEC standard
tests, real time instrument control for custom test set up and op¬
timisation and a comprehensive range of test sequencing,
programming and reporting functtons.
For further information circle 210 on the reader service
coupon or contact Westinghouse Industrial Products, 179 - 185
Normanby Road, South Melbourne 3205; phone (03) 676
8888.
Portable infrared thermometer
Weighing only 390 grams, the new M100 series portable IR
thermometer from Mikron Instrument can detect temperature
abnormalities in machinery and industrial processes without
contact. A precise laser aiming beam allows accurate targeting
and low fatigue operation. Rechargeable NiCad batteries pro¬
vide up to 20 hours operation.
Called the Hot Spotter, the instrument measures and records
temperatures from -50° to +500°C at distances up to 200cm.
All the operator does is aim the laser beam and pull the trigger.
According to the manufacturer, the unit is ideal for preventa¬
tive maintenance and detecting a variety of temperature related
faults, before serious damage occurs.
Applications include anticipating bearing failures, electri¬
cal power and switching faults, blocked steam traps or
deteriorating insulation and temperature fluctuations in
moving process materials.
For further information circle 211 on the reader service
coupon or contact W&B Instruments, PO Box 189, Carlton
South 3053; phone (03) 347 0866. ❖
ELF/VLF METER
CONSULTEC ELECTRONICS
is proud to announce the arrival of the TESLATRONIC
INC range of Low Frequency Magnetic Field Meters.
TESLATRONICS offers a complete line of accurate and low
cost Digital Milligaussmeters with a wide range of features
and options suitable for the safety conscious Professional.
Internationally, these meters are used by hundreds of
Utility Companies, Consultants, Health and Safety
Managers and Field Service Technicians in situations where
accuracy and reliability are critical.
The MODEL 50 is a precision, single axis instrument
designed to measure ELF magnetic field emissions from a
wide variety of sources found in the workplace.
The MODEL 60 is a precision, single axis instrument which
can measure both ELF and VLF magnetic field emissions
and is highly suitable for establishing compliance to the
Internationally recognised Swedish MPR 2 standard.
The MODEL 70 is the top of the line, three axis, precision
instrument designed to make accurate spot magnetic field
measurements in the ELF /Power frequency band.
STANDARD FEATURES
Precision A to D Converter
ContinuouslyAutoranging
ELF Range 0.1 to 1999 mG
60 Hour Power Life
Selection of Options
One Year Warranty
CMOS Microprocessor
Calibrated at 50Hz
VLF Range 0.01 to 1999 mG
Low Battery Indicator
Deluxe Carry Case
Cal Report Available
For further information and pricing details
please contact
CONSULTEC SALES
Ph: (03) 585 1159
or Fax: (03) 584 1169
READER INFO NO. 33
Silicon Valley
NEWSLETTER
Gates & Spielberg
in interactive venture
It was only a matter of time before the
biggest name in Hollywood would team
up with the most powerful figure in the
personal computer industry. A week
after co-founder Paul Allen invested
US$500 million in Steven Spielberg’s
new DreamWorks studio, Microsoft
chief Bill Gates held a joint press con¬
ference with Spielberg to announce a
joint venture to develop interactive
entertainment software.
Microsoft and DreamWorks each
will contribute half of the US$30
million start-up funding for the
‘DreamWorks Interactive’ venture,
which will focus initially on produc¬
ing adventure games and interactive
stories. The new company will be based
largely in Los Angeles, with a smaller
group near Microsoft head¬
quarters in Redmond.
“I’m spoiled,” said Spiel¬
berg, who wore a black
baseball cap with the yellow
logo of ‘Bob’, Microsoft’s
new graphically oriented
software system. “I worked
with the best studios and the
best actors, and it would be
silly to get into the interac¬
tive business without Micro¬
soft. They’re the best com¬
pany in the world. It does
seem like a marriage that was
destined to happen.”
Industry analysts applauded
the deal, saying it will lend
legitimacy to the multimedia
industry and will help expand
the market for CD-ROMs and
other interactive software.
“These guys are obviously
very talented, and what
they're doing can only help
this industry’’, said Tom
Kalinske, chief executive of
Redwood City-based Sega of
America.
The new company is ex¬
pected to come up with as
many as two dozen titles a
year, with its first original in¬
teractive products available for
Christmas 1996 and its first potential
projects based on its movies and
television shows available the following
year. Gates said the company will get
immediate help from a group of
Microsoft programmers and would have
the necessary combination of talents to
make interactive technology work.
Micron plans
US$1.3B chip factory
In a sign that the boom in semicon¬
ductor sales is far from coming to an
end, US memory chip maker Micron
Technology has announced its most
ambitious expansion project yet, saying
it has decided to build a US$1.3
billion semiconductor plant in Utah.
The facility will employ 35(X) people at
full capacity.
Construction on the new plant will
start this spring. It will be located in
Utah County, south of Salt Lake City.
The new plant is part of Micron’s expan¬
sion plan which calls for the doubling of
its semiconductor manufacturing
capacity during the next four years.
The Utah site was selected over two
other finalists: Omaha in Nebraska,
and Oklahoma City. Micron Chief Ex¬
ecutive Officer Steve Appleton said the
company liked Utah County’s proximity
and tax package.
Utah County offered tax increment
financing for the plant and to pay for up
to US$25 million in infrastruc¬
ture improvements such as sewer,
power, roads and water. The Utah Legis¬
lature also added a sales tax exemp¬
tion for replacing manufacturing
equipment, to one already on the books
for purchasing new machinery.
As an added bonus for
Micron, the proposed site is a
short distance from the
renowned Brigham Young
University and the University
of Utah. Micron had said it
wanted to be near a university
that could meet its employees’
continuing and advanced
education needs.
1" 1.5GB hard
drives by 2001
One-inch disk drives storing
1.5 gigabytes of data will be
available for use in laptop
computers as early at the year
2001, according to a team of
researchers from IBM and
Carnegie-Mellon University
who discussed their views of
future data storage technology
at a gathering of physicists in
San Jose.
The tiny future disks, they
said, will be made using such
materials as gold, platinum or
palladium. A major challenge
will be to make the recording
heads ‘fly’ so close to the sur¬
face of the disk that a mere
fingerprint on the platter
It could only happen at a US computer show! At the
latest Comdex, in Las Vegas , one of the stands
was offering free samples to anyone prepared to
put on these top heavy Sumo wrestling outfits and
have a go’. They had no shortage of takers.
124
ELECTRONICS Australia, June 1995
would be a mountain-sized obstacle. The
tiny drives will find their way into more
than just personal computers, where they
could provide the user with a built-in
complete reference library. They are also
likely to find uses inside telephones, fax
machines, and voice mail systems.
“To have these by 2001 is not a
stretch of the imagination”, said Mark
Kryder, a professor at Camegie-Mellon.
“Everybody seems to take it for granted
that this is simply a progression of the
growth line magnetic storage has been
on for the last two or three years.”
For much of the past two decades,
disk drive storage capacity has increased
at the rate of 20% every year. But during
the past couple of years, thanks to new
recording techniques, that rate of in¬
crease has reached about 60%.
To keep up the pace, however, “One
has to come up with better materials”
for both the magnetic platters and the
recording heads, said Dieter Weller, a re¬
searcher at IBM’s Almaden Research
Center in San Jose — which has been
responsible for the bulk of IBM data
storage innovations. Weller said his lab
is experimenting with a coating
made of an iron-platinum compound,
measuring only about two or three
atomic layers in thickness.
Weller said with such a thin coating
the recording head would have to
hover over the surface of the disk at just
eight ten-millionths of an inch, rotating
at the speed of about 11,000 revolu¬
tions per minute.
Both the IBM and other researchers
cautioned that magnetic disk drives
eventually would reach physical limita¬
tions, because the properties of mag¬
netic fields prohibit storing more than
about 100 billion bits per square inch.
After that, computers might store data
using arrays of miniature electron
microscopes to manipulate individual
atoms — technology that is at least 10
years away, said Hewlett-Packard re¬
searcher Gary Gibson.
3Com in two
acquisition moves
Corporate network products maker
3Com has announced it will pay
US$240 million in stock to acquire two
companies that supply computer net¬
working products.
3Com, based in Santa Clara, will buy
Primary Access of San Diego for
US$170 million and Sonix Communica¬
tions in the United Kingdom for US$70
million in stock. Both companies will
become wholly owned subsidiaries of
3Com, to be known as 3Com Primary
Access and 3Com Sonix respectively.
Primary Access gives 3Com a
presence in high speed networks that
replace various phone lines, data links
and modem lines with a single network.
SILICON VALLEY
HIRING ‘FRENZY’
First there was Silicon Graphics,
announcing plans to hire 3000 new
workers in 1995. Then came semi¬
conductor equipment maker Applied
Materials, saying it is in the process
of adding 2900 new jobs. National
Semiconductor weighed in, saying it
is hiring 200 new people, and finally
Lam Research, another chip equip¬
ment producer said its payroll will
swell by 1400 this year.
It is a hiring spree, the likes of
which has not been seen in Silicon
Valley since the mill 1980s at the
height of the first personal com¬
puter boom market. The question
remains how long it can last, and
whether there are enough people to
fill the vacancies.
Silicon Valley is not the only area
to benefit from the three year boom
in personal computer, software,
communications, and semiconductor
sales. About half the new jobs an¬
nounced by Applied and others will
be located outside the Valley. That is
particularly true in the area of
manufacturing jobs, as most firms
have relocated production operation
outside of the Valley where the cost
of living is too high for low to
medium skilled labour.
Intel, for example, is in the
process of adding several wafer fabs
costing more than US$ 1 billion
each. All but one are to be located
outside of the Valley.
CompuServe, for instance, uses Primary
Access to help link consumers to its
computer network system.
Sonix, meanwhile, provides corpora¬
tions with hybrid phone lines that
can deliver both data and voice
simultaneously. In the United
Kingdom, Sonix has captured 46% of
the ISDN market.
IBM to invest US$600M
in chip expansion
In yet another major semiconductor
plant expansion, IBM has announced
that it will invest over US$600 million
to expand its fast growing micro¬
electronics business.
Merchant market sales for IBM
Microelectronics products and services
have increased significantly in the past
two years, driving the need for addition¬
al investment. In 1994, IBM’s merchant
microelectronics revenues were ap¬
proximately US$1.7 billion, more than
double the 1993 sales.
Besides its own IC products, IBM has
become a major source for contract
manufacturing. Among the most visible
deals, the company has become the main
manufacturing resource for Cyrix and
NexGen, two firms developing clones of
the Intel x86 series of microprocessors.
“Our vision is to become a leading
supplier of highly competitive semicon¬
ductor products in the merchant market,
and these investments will move us
closer to that goal”, said Michael Attar-
do, general manager, IBM Micro¬
electronics Division.
Attardo said this capital investment
will allow IBM to better balance its in¬
vestments among high potential
products, including PowerPC micro¬
processors and embedded controllers,
memory, high performance x86-com-
patible microprocessors, microwave
digital signal processors and other
products aimed at computer, consumer
and communications segments.
CD-ROM sales
soared in 1994
Dataquest has confirmed what was
generally known: that CD-ROM sales
are soaring in the face of the rapidly
growing popularity of multimedia-
capable personal computers. Some 53.9
million CD-ROM programs were sold in
1994, Dataquest said, a 227% increase
from 16.5 million in 1993.
Microsoft shipped the most titles, at
8.3 million units. Trailing Microsoft’s
15.4% market share is Mindscape, with
12.4%; Grolier, with 9.4%; Electronic
Arts, with 5.5%; and Broderbund
Software with 4.7%.
“Games, reference books, and educa¬
tion titles were the big hits of 1994”,
said Bruce Ryon, director and principal
analyst of Dataquest’s Multimedia
Worldwide program, in a statement. He
noted that as developers battle it out for
retail shelf space, profit margins on in¬
dividual CD-ROM titles are being
squeezed. The average factory selling
price of CD-ROM titles has sunk to a
low of US$11 a copy.
CD-ROM titles that come bundled
with multimedia computers and kits ac¬
count for 66% of all CD-ROM title
shipments, according to Dataquest’s
1994 figures. Some computers come
with as many as 50 CD-ROM titles. ❖
ELECTRONICS Australia, June 1995
125
Computer News
and New Products
Instrument
calibration software
4S+P I/O card
The Magma 4+1 Sp is an SBus expan¬
sion board that combines four high speed
asynchronous serial ports with full
modem control and one Centronics paral¬
lel port. The board is compatible with
Sun Microsystems SPARC computers.
The serial ports operates up to
115.2kb/s and were designed to interface
with high speed modems, terminals or
any other RS-232 device. The parallel
port operates at speeds up to 250,000
char/sec and can be used to connect to
high speed printers or plotters. Both serial
and parallel ports operate with minimal
CPU overhead, achieved by the use of
specialised RISC processors with built in
buffers. The buffering allows the
hardware and software to minimise the
number of CPU interrupts.
The supplied device drivers are
designed to take advantage of the
board’s high speed serial and parallel
capabilities. The driver is compatible
with Solaris 2.x and SunOS 4.1+ and
supports all features of both systems.
The board is priced at $945.
For further information circle 163 on
the reader service coupon or contact
Graphics Computer Systems, 22
Harker Street, Burwood 3125; phone
(03) 888 8522.
A new version of Fluke Corporation’s
MET/CAL and MET/TRACK calibra¬
tion information management software
is now available, running under Win¬
dows. It provides simplified system
configuration, new instrument interfaces
and 200 new procedures for a wide range
of test instrumentation.
MET/CAL is a PC-based software
package that automates the calibration
process. It lets users create, edit and
document calibration procedures, execute
tests under computer control using a wide
variety of manual and automated stand¬
ards, and collect and report test results
and issue calibration certificates.
MET/CAL is a measurement oriented
asset database that permits users to main¬
tain and report data about the location
and application of measurement equip¬
ment, calibration history, standards used,
traceability to and from national stand¬
ards, repair history and cost, as well as a
host of user defined information. MET/
TRACK can be used in a single user ap¬
plication or over a local area network.
Working together, MET/CAL and
MET/TRACK satisfy the documentation,
reporting and control requirements
specified in standards and regulations
such as ISO 9000, MIL STD 45662A,
FDA GMP, OSHA and others.
For further information circle 161 on
the reader service coupon or contact
Process Control System
The Simatic PCS is the first process control system from
Siemens to combine the power of the distributed control sys¬
tem with the flexibility of the Simatic range of program¬
mable logic controller. Since all the process control
functions are configurable, the Simatic PCS offers a high
level of system flexibility.
The system has scaleable architecture. Entry level systems
can start with a single supervisory workstation and can be ex¬
panded to a full blown system with 16 operator workstations.
The system can be supplied with an ORACLE interface for
seamless integration into management information systems
running ORACLE database.
Existing SIMATIC S5 and SIMATIC TI users can upgrade
their control system to the SIMATIC PCS and take advantage
of the distributed control capabilities.
For further information circle 162 on the reader service
coupon or contact Siemens, 383 Pacific Highway, Artarmon
2064; phone (02) 436 8624.
126
ELECTRONICS Australia, June 1995
READER INFO NO. 34
I/O card for notebooks
National Instruments has released a
low power, low cost parallel digital I/O
card for computers with a PCMCIA slot.
The DAQCard-DIO-24 is a type II
PCMCIA card that can be used for
laboratory testing, production testing, and
industrial process monitoring and control
applications. It includes NI-DAQ and
DAQWare software, and is compatible
with the company’s LabVIEW, Lab-
Windows, and LabWindows/CVI ap¬
plication software products.
The card can connect notebook com¬
puters to peripherals with parallel digital
I/O, BCD compatible panel meters and
test equipment, SSR series solid state
relay boards, and so on.
The DAQCard DIO-24 uses a 24-bit
PPI, which can be further divided into
three 8-bit ports. It features high speed
transfer rates up to 250kb/s. With a
Philips Scientific & Industrial, 34 Water¬
loo Road, North Ryde 2113; phone (02)
888 8222.
‘Fastest’ docket printer
The Star Micronics SP317 is claimed
to be the fastest impact docket printer in
the world. Using two nine inch print
programmable interval timer, users can
generate periodic interrupts for pattern
generation. It can operate in either a
unidirectional or bi-directional mode,
generate interrupt requests, and hand¬
shake with peripheral equipment. All
functions of the card are software con¬
figurable. The PCMCIA bus interface has
16-bit data paths with interrupt-genera¬
tion circuitry.
For further information circle 164 on
the reader coupon or contact National In¬
struments, PO Box 466, Ringwood 3134;
phone (03) 879 9422.
heads, the SP317 prints bi-directionally at
a rate of just under six lines per second.
The printer has been designed for use
with electronic devices such as POS
units, data storage devices and peripheral
equipment used with bank terminals. It
allows data to be received while printing
is in progress and two external equipment
drive circuits enable control of cash
drawers and other equipment via a con¬
trol switch. The standard print colour is
violet, however black is optional with the
use of a cassette ribbon. Commands for
expanded width characters, upside down
characters and underlined characters are
provided. The printer comes with an RS-
The world’s best
data logger just
Now you can log up to 150 analog
and 84 digital inputs with a single
Datataker 500 or Datataker 600. You
get up to 44 digital outputs as well.
It’s simply a matter of adding
Channel Expansion Modules.
Channel Expansion modules
support all the standard
Datataker features.
Any sensor, any mix. With
Datataker you choose. There are no
restrictions to working the way you want. No more PC
cards and compatibility problems. Datatakers work with all
computers, any operating system.
Whatever your application there is a Datataker solution. You can
network Datatakers on a standard twisted pair, over telephone and radio
modems or via satellite link.
Call our application engineering staff to discuss your application, get
full information or arrange a demonstration.
Data Electronics 7 Seismic Court, Rowville Vic. 3178.
Tel: (03) 764 8600. Fax: (0.3) Tw 80<r
PASSION FOR HIGH PERFORMANCE
Tweeters
Midranges
Woofers
Speaker Kits
distributed by
^Technologies
L an ME Sound Pty Ltd Subsidiary
PO Box 50 Dyers Crossing, NSW 2429
Ph: 065 502200/54 Fax: 065 502341
AUDAX RETURNS TO AUSTRALIA
ELECTRONICS Australia, June 1995 127
READER INFO NO. 35
COMPUTER NEWS AND NEW PRODUCTS
232C serial interface, an optional current
loop and RS-422A serial interface. It
retails for $980.
For further information circle 172 on
the reader service coupon or contact Star
Micronics, 107 Asquith Street, Silver-
water 2141; phone (03) 748 4300.
Hex speed CD-ROM drive
SCSI Corporation has available what it
claims as the world’s first six times speed
CD-ROM drive. Plextor’s 6PleX PX-63
CH is also claimed to offer the fastest
throughput and access time available in
CD-ROM performance, with 922kB/s
data transfer and a 145ms random access.
The unit has a 256KB buffer and a
100,000 hour (7% duty) mean time be¬
tween failures (MTBF) and is backed by
a two year parts and labour warranty.
The internal 6PleX PX63CS drive has
a list price of $1167 (inc tax), while the
external 6PleX PX65CS unit has a list
price of $1367 (inc tax).
For further information circle 170 on
the reader service coupon or contact
SCSI Corporation, 19/9 Hudson Avenue,
Castle Hill 2154; phone (02) 894 6033.
Disk drive for audio/video
Micropolis has announced a new
generation of AV drives called the AV
Gold Javelin series. The new drives fea¬
ture a minimum sustained transfer rate of
4MB/sec, an improvement in speed of
more than 35% over the company’s pre¬
vious disk drive products.
The new drives have been optimised
for continuous and sustained delivery of
data, eliminating delays in the data
stream that cause frame dropouts and
jerkiness in digital audio/video playback
or recording.
The drives are performance tuned for
continuous throughput and maximum
bandwidth, offering the high, uninter¬
rupted data rates required for enhanced
digital and audio performance in applica¬
tions such as multimedia, digital video
editing and video servers. The series fea¬
tures a 650,000 hour mean time between
failure and have a five year warranty
when purchased through an authorised
Micropolis distributor or reseller.
For further information circle 171 on
the reader service coupon or contact
Micropolis, 201 Miller Street, North Syd¬
ney 2060; phone (02) 959 2298.
Fibre optic modem pair
The OSD3115/OSD3117 is a fibre
optic modem pair for the transmission
of high quality video and stereo audio.
The OSD3115 transmitter accepts
balanced or unbalanced video and
audio. Termination resistors (75 ohms
video, 600 ohms audio) are installed on
the board and can be linked by the user if
required. When unterminated, the video
input impedance is greater than 10k ohms
and the audio input impedance is greater
than 20k ohms.
The complete system offers greater
than 6MHz bandwidth on the video and
15kHz for the audio channels. It will
operate over at least 4km of standard
multimode fibre while maintaining signal
to noise ratios exceeding 50dB for the
video and 55dB for the audio.
Units are available either as Eurocard
size cards or in standalone 240V AC
powered enclosures.
For further information circle 165 on
the reader coupon or contact Optical Sys¬
tems Design, PO Box 891, Mona Vale
2103; phone (02)913 854
Recycled floppy disks
The GreenDisk is a recycled floppy
disk that is claimed to cost less and to
perform better than many new disks.
GreenDisks start life as premium
quality disk, used by software publishers
such as Microsoft. Constant upgrading of
software means that many disks are not
sold, before becoming superseded.
Software companies were dumping
thousands of these ‘once used’ disks,
creating a threat to the environment, as
disks take up to 450 years to break down,
if dumped as landfill. The disks are col¬
lected, wiped clean, formatted and
relabelled as premium quality Green-
Disks. The disks are available from
Green world Office Products.
For further information circle 169 on
the reader service coupon or contact
Greenworld Office Products, PO Box 50,
Berwick 3806; phone (03) 796 2413. ❖
Australian Comp uters & Peripherals from JED... Call for data sheets.
Australia’s first
PC/104 computer.
The photo to the left shows the
new JED PC540 single board
computer for embedded scientific
and industrial applications.
This 3.6" by 3.8” board uses
Intel’s 80C188EB processor,
with two serial ports (one with
RS485), 3 timers, R-T-clock, I C bus, etc. We added a Xilinx gate array
with 40 I/O lines for user I/O. It has 128 kB of RAM, and runs programs in
C (using the $179 Pacific C complier). Or it can run Datalight’s ROM-DOS
from a 512 kB Am29F040 FLASH chip. The basic board is $350 one-off.
JED Microprocessors Pty. Ltd
$125 PROM
Eraser, complete
with timer
$300 PC PROM
Programmer. , c , t --
^ (Sales tax exempt prices)
Need to programme PROMs from your PC?
This little box simply plugs into your PC or Laptop's parallel printer port and reads
writes and edits PROMs from 64Kb to 8Mb.
It does it quickly without needing any plug in cards
Office 7, 5/7 Chandler Road, Boronia, Vic., 3155. Phone: (03) 762 3588 Fax: (03) 762 5499
READER INFO NO. 36
128
ELECTRONICS Australia, June 1995
WOOD FOR CHIPSJNOOD FOR CHI PS... WOOD FOR CHIPSJMDOD FOR CHIPSJWOOD FOR CHIPSJWOOD FOR CHITWOOD FOR CHIPS..WOOD FOR CHIPS^WOOD FOR CHIPSJVOgD FOR CHIPS ... WOOD
FOR CHIPS... WOOD FOR CHIPS... WOOD FOR CHIPS... WOOD FOR CHI PS... WOOD FOR CHI PS... WOOD FOR CHIPS... WOOD FOR CHI PS... WOOD FOR CHIPS
As we
Last At These Prices!
Hakko 926 Soldering Station
The Hakko 926 is a super-quick heat-up (3 sec cycle) and fast
recovery iron The built-in ceramic heater maintains temperature to
within 0.5 C of the setting. Yes this is an ADJUSTABLE temperature
iron covering the range from 200°C to 480°C using a full wave zero-
cross^ switching system. Meets MIL-STD-2000 and operates at
Some people are asking $250!
sttSFsss&sz;
Our’s are still only
$ 199.95
We keep 18 Hakko Tips for the 926 in stock plus spare
parts, solder etc and other Irons in the Hakko range
DIC SC-7000 DeSoldering
Tool ESD* Protected
• Now with 100W ceramic heater
• Sensor feedback digital temperature
• ‘ Special antistatic housing and zero crossover switching to protect
sensitive components
• Suction/Hot air blow switch -
suck for desoldering,
blow for SMD removal
• Work on up to 12 layer boards Call for tax-free pricing
$630
inc tax
Includes
FREE SMD
Plunger for
use with
optional
heads
Special Function ICs
14411 Bit Rate Fqcy Gnrtr $28.70
14490P Hex Switch Debounce $5.15
145026P Remote Control Encdr $2.55
145027P 9 Bit Trinary Dcdr $3.70
145028P Remote Control Dcdr $4.80
ICL8038CCJD Function Generator
ICM7209IPA 10MHz Clock Gen
Precision Clock
CMOS Timer
See LMC555CN
See LMC555CN
Dual CMOS Timer
Precision Timer
Volt/Freq. Comp
Timer
Dual Timer
Ultrasonic Detector
Freq./Voltage Comp
Frequency/Voltage Co $4.75
Frequency/Voltage Co $2.55
Frequency/Voltage Co $3.15
ICM7213IPD
ICM7240IJE
ICM7555CN
ICM7555IPA
ICM7556IPD
LM322N
LM331N
LM555CN
LM556CN
LM1812N
LM2907N
LM2907N-8
LM2917N
LM2917N-8
LM3905N
LM3909N
LM7555CN
LMC555CN
LMC556CN
MC33030P
$12.35
$12.75
$17.70
$5.75
$3.55
$1.75
$ 12.20
$0.80
$2.80
$14.20
$2.60
Precision Timer
LED Flasher/Oscil
See LMC555CN
CMOS Timer
Dual CMOS Timer
Stepper Driver
$1.40
$2.85
$1.15
$3.00
$11.75
$1.40
MM5369AA/N 3.58MHz/60Hz Divider$3.90
NE558N Quad Timer $2.40
SAB6456A 1GHz Swtchbl Presclr $4.00
TDA1024 Zero X T riac T rigger $6.00
TEA1100 Fast Battery Charger $14.25
TEA5501 Encoder/Decoder $7.60
UC3906N Lead Acid Charger $14.85
VRSTR-130V-7MM
130V 7mm Varistor
VRSTR-275V-12IVIM
275V 12mm Varistor $1.40
XR-2206CP Function Generator $10.00
XR-2209CP Precision Oscillator
XR-2240CP CMOS Timer
14409 Binary/Phone Pulse
AM7910PC Until Sold
LM565CN Phase Locked Loop
LM566CN Voltage Cont Oscltr
LM567CN Tone Decoder
LMC567CN CMOS Tone Decoder
MC14LC5436P DTMF Decoder
MF4CN-50
MF10CCN
NE564N
NE570N
NE571N
NE572N
TP5088N
TP5089N
TP5395N
$6.35
$3.00
$11.55
$28.00
$4.60
$1.50
$1.05
$2.40
$5.75
4th Order CMOS Filter $4.45
Dual Active Filter $5.20
Dgtl Phase Lock Loop $3.90
Compander
Compander
Compander
DTMF Tone Dialler
DTMF Dialler
Until Sold
$5.70
$4.05
$ 6.00
$3.60
$2.40
$10.90
Audio Leads
AL-100 5 Pin DIN.PIg to Pig
AL-102 5 Pin DIN/4xRCA Pigs
AL-103 4 x RCA/4 x RCA Pigs
AL-105 8M 6.35mm Stero P to S
AL-107 RCA Plug to 2 RCA Skts
AL-1 08 1.2M 3.5mm Pig to Skt
AL-116 RCA Plug/PIg
AL-116L 3.0M RCA Pig to RCA Pig
AL-130 1 2M 5 Pin DIN to 2xRCA
AL-142 2 RCA to 2 RCA Pigs
AL-142L 2 RCA Pigs to 3.5mm Pig
GL-8 Guitar Lead
Fly Leads
FL-1 1.8M 75 Ohm Plug/PIg
FL-2 1.8M 75 Ohm Plug/Skt
FL-4 4.5M 75 Ohm Plug/PIg
FL-5 10M 75 Ohm Plug/PIg
FL-6 4 5M 75 Ohm Plug/Skt
FL-7 10M 75ohm Pig to Skt
FL-8 1 8M 75ohm to F Skt
FL-21 1 5M Plug to Pig
FL-22 3.75M Pig to Skt
FL-23 5M 75ohm Pig to Skt
Power Leads
Computer Cord
$7.15
$8.15
$8.15
$9.95
$5.05
$3.95
$4.05
$4.95
$4.95
$5.05
$4.95
$14.30
$5.05
$5.05
$5.95
$9.95
$5.95
$3.45
$6.15
$6.75
$8.75
$10.95
IEC-CORD
PL-1
PL-2
PL-7
PL-8
$7.95
Power Lead.Fig-8 2.0m $8.15
Power Lead.Grooved Rect $8.15
Power Lead Oval Socket $15.95
IEC Extension Cord
$16.95
TV Accessories
AT-6 TV Attenuator
DDF772 Splitter/Coupler Coax
DDF774 75 Ohm TV & FM Splitter
MHB-2 Msthd Baiuns 300/75 Ohm $5.10
MHB-4 Msthd Baiuns 300/75 Ohm $5.70
SUV-7 75 ohm Splitter
TV-1 Baiun 300/75 Ohm
TV-2 Baiun 75/300 Ohm
TV-3 Coax Entry Box
TV-3A Coax Entry Box
TV-4 Splitter Entry Box
TV-5 Coax Entry Plate
TV-6 Mini Wall Plate
TV-7 Standard Plate,One Hole
TV-9 75 Ohm Insert
TV-10 300 Ohm Insert
TV-10A 300 Ohm Insert
TV-16 UHF/VHF Band Separator
TVS-2 TV Game/Computer Switch $7.05
VDK-2 Video Dubbing Kit $25.95
$5.00
$5.95
$7.95
$3.90
$2.55
$2.55
$3.05
$3.95
$5.05
$7.15
$ 2.00
$4.00
$3.00
$ 2.00
$ 2.00
$9.05
Your Complete Guide To The Huge Range of
CONNECTORS from Geoff Wood (Part 2))
Following the
we’re listing al
comprehensive our range is. We suggest you photocopy
or save this page for future reference!
blowing the popularity of our Semiconductor Listing
e're listing all our connectors - just to show you how
MACHINE SOCKETS
IC-MACH-06 6 Pin Machine Skt
IC-MACH-08 8 Pin Machine Skt
IC-MACH-14 14 Pin Machine Skt
IC-MACH-16 16 Pin Machine Skt
IC-MACH-18 18 Pm Machine Skt
IC-MACH-20 20 Pin Machine Skt
IC-MACH-22 22 Pin Machine Skt
IC-MACH-24 24 Pin Machine Skt
IC-MACH-24/SKINN
24 Pin Skinny DIP
IC-MACH-28 28 Pin Machine Skt
IC-MACH-32 32 Pin Machine Skt
IC-MACH-40 40 Pin Machine Skt
IC-MACH-64 64 Pin Machine Skt
PLCC
IC-PLCC-28 28 Pin Ldless Carrier
IC-PLCC-32 32 Pin Ldless Carrier
IC-PLCC-44 44 Pin Ldless Carrier
IC-PLCC-52 52 Pin Ldless Carrier
IC-PLCC-52-SMD
SMD PLCC Socket
IC-PLCC-68 68 Pin Ldless Carrier
IC-PLCC-84 84 Pin Ldless Carrier
IC-SIMM-30 30 Way SIMM Socket $8.05
SOLDER
IC-TIN-06 6 Pin Solder Skt $0.20
IC-TIN-08 8 Pin Solder Skt $0.10
IC-TIN-14 14 Pin Solder Skt $0.15
IC-TIN-16 16 Pin Solder Skt $0.15
IC-TIN-18 18 Pin Solder Skt $0.15
IC-TIN-20 20 Pin Solder Skt $0.20
IC-TIN-22 22 Pin Solder Skt $0.25
IC-TIN-24 24 Pin Solder Skt $0.40
IC-TIN-24-SKINNY
24 Pin Skinny DIP $0.40
IC-TIN-28 28 Pin Solder Skt $0.25
IC-TIN-40 40 Pin Solder Skt $0.35
TRANSITION SOCKETS
$0.35
$0.45
$0.75
$0.90
$0.95
$1.15
$1.15
$1.30
$1.40
$1.60
$2.75
$2.30
$3.30
$3.15
$2.95
$3.50
$3.75
$3.75
$2.55
$5.05
IDC-TRANS-10-P
IDC-TRANS-10-PCB
IDC-TRANS-10-S
IDC-TRANS-14-P
IDC-TRANS-14-S
IDC-TRANS-16-P
IDC-TRANS-16-S
IDC-TRANS-20-P
IDC-TRANS-20-S
IDC-TRANS-26-P
IDC-TRANS-26-S
IDC-TRANS-34-P
IDC-TRANS-34-S
IDC-TRANS-40-S
IDC-TRANS-50-S
IDC-TRANS-60-S
10 Way Pig $4.60
PCBPrllel Pins$1 .55
10 Way Skt $0.60
14 Way Pig
14 Way Skt
16 Way Pig
16 Way Skt
20 Way Pig
20 Way Skt
26 Way Pig
26 Way Skt
34 Way Pig
34 Way Skt
40 Way Skt
50 Way Skt
60 Way Skt
$1.55
$1.35
$1.60
$0.85
$7.35
$0.80
$1.95
$0.85
$11.05
$0.90
$1.30
$1.90
$3.15
HEADERS
BOX RIGHT ANGLE
IDC-HDR-BX-RA-10 10 Way Boxed $1.45
IDC-HDR-BX-RA-14
IDC-HDR-BX-RA-16
IDC-HDR-BX-RA-20
IDC-HDR-BX-RA-26
IDC-HDR-BX-RA-34
IDC-HDR-BX-RA-40
IDC-HDR-BX-RA-50
IDC-HDR-BX-RA-60
BOX STRAIGHT
IDC-HDR-BX-ST-10
IDC-HDR-BX-ST-14
IDC-HDR-BX-ST-16
IDC-HDR-BX-ST-20
IDC-HDR-BX-ST-26
IDC-HDR-BX-ST-34
IDC-HDR-BX-ST-40
IDC-HDR-BX-ST-50
IDC-HDR-BX-ST-60
14 Way Boxed $ 2.10
16 Way Boxed $1.05
20 Way Boxed $2.80
26 Way Boxed $3.35
34 Way Boxed $3.85
40 Way Boxed $5.70
50 Way Boxed $6.40
60 Way Boxed $7.80
10 Way Boxed $0.50
14 Way Boxed $1.75
16 Way Boxed $0.85
20 Way Boxed $1.30
26 Way Boxed $1.70
34 Way Boxed $4.05
40 Way Boxed $4.35
50 Way Boxed $5.95
60 Way Boxed $6.80
RIGHT ANGLE WITH LATCHES
IDC-HDR-RA-10
IDC-HDR-RA-14
IDC-HDR-RA-16
IDC-HDR-RA-20
IDC-HDR-RA-26
IDC-HDR-RA-34
IDC-HDR-RA-40
IDC-HDR-RA-50
IDC-HDR-RA-60
IDC-HDR-RA-64
10 Way
14 Way
16 Way
20 Way
26 Way
34 Way
40 Way
50 Way
60 Way
64 Way
STRAIGHT WITH LATCHES
IDC-HDR-STR-10
IDC-HDR-STR-14
IDC-HDR-STR-16
IDC-HDR-STR-20
IDC-HDR-STR-26
IDC-HDR-STR-34
IDC-HDR-STR-40
IDC-HDR-STR-50
10 Way
14 Way
16 Way
20 Way
26 Way
34 Way
40 Way
50 Way
$1.65
$2.35
$2.55
$3.20
$4.10
$5.35
$5.75
$7.90
$8.60
$10.05
$1.05
$1.95
$1.90
$2.35
$3.40
$4.40
$4.90
$6.50
PIN HEADERS
PIN-HDR-LNG-1X36
PIN-HDR-RA-1X40
PIN-HDR-RA-2X40
PIN-HDR-STR-1X40
PIN-HDR-STR-2X40
Straight 1x36 $4.10
R/A 1x40 Pins $1.30
R/A 2x40 Pins $1.95
Straight 1x40
Straight 2x40
$0.65
$1.15
0.1 Blk Per 10
0.1 Blk Per 100
$0 65
$6.05
0.1 Blk Per 500$30.30
SHUNTS
SHUNT-BLK/10
SHUNT-BLK/100
SHUNT-BLK/500
SQUARE POST
HEADER SOCKETS
SQP-DIL-MACH-50 50 Way $22.00
SQP-SIL-MACH-36 36 Way $8.00
Video Leads
VL-1 1.5m BNC Plug/PIg $8.75
VL-2 3M 75 Ohm BNC Plug/PIg $4.00
VL-5 RCA to RCA $4.40
VL-6 1 5m 75ohm BNC to RCA $6.70
VL-7 1 5m 75 Ohm RCA/Coax PI $5.00
VL-9 20cm 5 Pin DIN to 4xRCA $6.05
VL-15 1.5m 6 Pin DIN Pig to P $8.05
VL-21 1 5m SCART TO 6 Pin DIN$10.00
DEGAUSSING WAND
240V Degaussing Wand $99.95
About to buy a
Multimeter?
Then check our prices for the best in the busines s
FLUKE
8.30am to 5.00pm Mon to Thurs., 8.30am to 4.30pm Friday.
Mail Orders add $5.00 min to cover postal charges.
Next day delivery in Sydney add $8.00.
All prices include Sales Tax unless stated otherwise.
Tax exemption certificates accepted if the line value
exceeds $10 00
BANKCARD, MASTERCARD, VISA, CHEQUES or CASH
cheerfully accepted. READER INFO NO. 11
LM3886 50W
Amplifier 1C
This is the 1C used in Silicon Chip’s 50W stereo amplifier
project (Feb 95) This monolithic 1C delivers slightly
more power than the LM3876. Output is 48W into 812
or up to 60W into 412 with a frequency response from
16Hz to 200kHz ±1dB! Input sensitivity is 870mV and
harmonic distortion is typically <0 005% Signal to
noise is 107dB unweighted. Only requires a handful of
parts to make a power amp with no complicated f iddlinq
to set up No quiescent adjustment, better thermal
stability and short-circuit proof 1 "?C
1C is only %> I L./O
LM1875 20Watt Power Audio Amp
Delivers 20W into 4 or 812 load using +25V supply. Can
get up to 30W into 812 with +30V. Minimum of external
parts. See Silicon Chip Dec 93 $4.40
Geoff Wood Electronics Pty Ltd
and Semtech (inc in N S W)
229 Burns Bay Road, Lane Cove West
NSW 2066 (Corner Beatrice Street)
Telephone : (02) 428 4111 Fax : (02) 428 5198
; WOOD FOR CHIPS... WOOD FOR CHIPS..WOOD FOR CHIPS... WOOD FOR CHIPS...WOOD FOR CHIPS... WOOD FOR CHIPS...WOOD FOR CHIPS..WOOD FOR CHIPS...WOOD FOR CHIPSJWOOD FOR CH!PS_ WOOD FOR
EA DIRECTORY OF SUPPLIERS
Which of our many advertisers are most likely to be able to sell you that special component,
instrument, kit or tool? It’s not always easy to decide, because they can’t advertise all of
their product lines each month. Also some are wholesalers and don’t sell to the public. The
table below is published as a special service to EA readers, as a guide to the main products
sold by our retail advertisers. For address information see the advertisements in this or
other recent issues.
Supplier
State
A
B
C
D
E
F
G
Altronics
WA
•
•
•
•
•
•
•
Companion Computers
VIC
•
Dick Smith Electronics
ALL
•
•
•
•
•
•
•
Emona Instruments
NSW
•
Geoff Wood Electronics
NSW
•
•
•
•
•
•
Jaycar Electronics
Eastern
•
•
•
•
•
•
•
Kalex
VIC
•
Macservice
VIC
•
RCS Radio
NSW
•
Rod Irving Electronics
Eastern
•
•
•
•
•
•
•
Scientific Devices
VIC
•
TECS
VIC
•
•
•
•
•
•
•
Wagner Electronics
NSW
•
•
•
•
KEY TO CODING:
A Kits and modules
B Tools
C PC boards and supplies
D Components
E 1C chips and semiconductors
F Test and measuring instruments
G Reference books
Note that the above list is based on our understanding of the products sold by the firms concerned. If
there are any errors or omissions, please let us know.
Electronics Australia Reader Services
SUBSCRIPTIONS: All subscription en¬
quiries should be directed to: Subscriptions
Department, Federal Publishing Co, PO Box
199, Alexandria 2015; phone (02) 353 9992.
BACK ISSUES: Available only until stocks
are exhausted. Price A$7.50 which includes
postage within Australia only. OVERSEAS
READERS SHOULD ADD A FURTHER
A$2.50 FOR EVERY BACK ISSUE RE¬
QUIRED.
PHOTOSTAT COPIES: When back issues
are exhausted, photocopies of articles can
be supplied. Price $7.50 per project or $15
where a project spreads over several issues.
PCB PATTERNS: High contrast, actual size
transparencies for PCBs and front panels
are available. Price is $5 for boards up to
lOOsq.cm, $10 for larger boards. Please
specify negatives or positives.
PROJECT QUERIES: Advice on projects
is limited to postal correspondence only
and to projects less than five years old.
Price $7.50. Please note that we cannot
undertake special research or advise on
project modifications.
Members of our technical staff are not
available to discuss technical problems
by telephone.
OTHER QUERIES: Technical queries out¬
side the scope of ‘Replies by Post’, or sub¬
mitted without fee, may be answered in the
‘Information Centre’ pages at the discretion
of the Editor.
PAYMENT: Must be negotiable in Australia
and payable to ‘Electronics Australia’. Send
cheque, money order or credit card number
(American Express, Bankcard, Mastercard
or Visa card), name and address (see form).
ADDRESS: Send all correspondence to:
The Secretary, Electronics Australia, P.O.
Box 199, Alexandria, NSW 2015; phone
(02) 353 0620.
PLEASE NOTE THAT WE ARE UNABLE
TO SUPPLY BACK ISSUES, PHOTO¬
COPIES OR PCB ARTWORK OVER THE
COUNTER.
METHOD OF PAYMENT: (Please circle correct method).
Credit Card:
Cheque:
Money Order:
Mastercard Expiry Date:
American Express
Visa
Bankcard
Name: .
Address:.
.Postcode:.
Back Isues:.
No.of issues required: $7.50=
No.of copies required: $5.00=
No.of copies required:...$15.00=
Total Payment Enclosed $
Photostat Copies:.
Signature:.
.(Unsigned orders cannot be accepted).
ADVERTISING
INDEX
Altronics.88-90
Arlec Holdings. 121
Bainbridge Marine. 109
Campad Electronics.96/7
Circuitworks.30
Consultec Electronics. 108,123
Data Electronics. 127
Delsound.39
Dick Smith Electronics.52-53
EA subscriptions offer. 19
Elect. Dev. & Sales. 17
Emona Instruments. 120
Geoff Wood Electronics. 129
Global Satellites.30
Griffith University. 114
Hewlett-Packard Australia.IFC
Hinton Information Serv.30
Hi-Tech Software. 122
Icom Australia.OBC
Instant PCBs.96/7
Jaycar Electronics.78-81
JED Microprocessors. 128
Kalex.38
Leprechaun Software. 105
Melbourne Satellites.23
Memory International. 11 1
ME Technologies. 127
Oatley Electronics.IBC
Obiat.45
Ocean Controls. 114
Peter Lacey Services.46
Philips Test & Measuring. 1 1
Protel Technology. 122
Radshield Australia. 114
RCS Radio.96/7
Rockby Electronics.95
Rod Irving Electronics.33,64-67
Royal Melb. Institute.63
Skandia Electronics. 1 15
Technical Applications.49
TECS Wholesale.31
Tortech.96/7
Vintage Wireless Radio Co.77
Vorlac.77
Westinghouse Brake Signal. 17
Your Computer magazine. 18
This index is provided as an additional ser¬
vice. The publisher does not assume any
liability for errors or omissions.
130
ELECTRONICS Australia, June 1995
COLOUR MONITOR
German made, used but
guaranteed 12" mains
powered colour computer
monitors, with bright Toshiba
tubes. 9-pin DIN connector
for signal inputs, brief
information supplied. We will
soon have a kit available to
make these sets into the
ULTIMATE MUSICOLOUR: a
new colour display for each
beat of music. Ideal for
experimenting with $40
12V-2.5W SOLAR PANEL SPECIAL
These US made amorphous glass
solar panels only need terminating
and weather proofing. We provide
terminating clips and a sheet of glass.
The terminated panel is glued to the
backing glass, around the edges only.
For improved looks, inexpensive
plastic L angle can be glued to the
edges. Very easy to make.
Dimensions: 305x228mm, Voc:
18-20V, Isc: 250mA. SPECIAL
REDUCED PRICE! $20 ea. or 4 for
$60. Each panel is provided with a
sheet of backing glass, terminating
clips, isolating diode and instructions.
A very efficient switching regulator kit
is also available: Suits 12-24V
batteries, 0.1-16A panels, $27. Also
available, a simple and efficient shunt
regulator kit, $5.
MOTORS
Small powerful GEARED AC motor.
1 RPM/60HZ/24V/5W. We supply
a circuit diagram that shows how to
power this motor from 12V DC:
Variable speed/full power (Bridge
output). Bargain priced: $9
MOTOR SPECIAL: These motors
can also double up as generators.
Type M9: 12V, I no-load = 0.52A -
15,800 RPM at 12V, 36mm dia,
67mm long, $5. Type M14: made
for slot cars, 4-8V, I no-load =
0.84A at 6V, at max efficiency I =
5.7A - 7500 RPM, 30mm dia,
57mm long, $5
LOW COST IR ILLUMINATOR
Has 42 high-output 880nm IR LEDs
(30mW <® 100mA ea), and a 7
transistor adjustable constant current
driver circuit Operates from 10-14V
DC, current adj range 5-600mA.
Compact PCB designed to replace lid
on a standard 82 x 53 x 28mm
plastic box.s Good for illuminating IR
responsive CCD cameras, IR and
passive night viewers, medical use.
Kit includes box, low price: $40
VEHICLE COMPUTER
Originally for bicycles, these
suit any moving vehicle with
wheels! 9-function computer
with speed, average speed,
maximum speed, distance,
odometer, timer, scan, freeze
frame memory, and a clock.
Microprocessor circuitry can
be adapted to work with
almost any wheel diameter.
Divide the wheel diameter in
millimeters by 6.8232, and
program the result into the
computer. $29.90
IR REMOTE SWITCH
Consists of a PCB and all on-board
components for an IR receiver with a
toggle output. Includes a new
commercial ready-made slimline IR
remote control transmitter, designed
for a CD player. Press any button on
the IR transmitter to toggle the output
on the receiver: The system has up to
20m range and also works from most
other IR remote controls! Receiver
has an 1C "front end" and operates
from 8-15V DC, and will drive a relay.
Transmitter operates from two AAA
batteries (Not supplied). Unbelievable
pricing: $18 Suitable 12V 8A relay
with 4kV isolation: $3, 12V DC
plugpack: $10
LOW COST PIR
PIR movement detector, based on a
single LSI 1C design, features simple
construction, even the lens assembly
snaps onto the PCB. Has every
possible feature: negligible power
consumption, adjustable daylight
disable with supplied LDR, 10m
range, variable alarm time, disable
input, 10A MOSFET output, 10-20V
DC operation. Fits into the smallest
zippy box! Complete kit (PCB & all
on-board components) for only $18
COMPONENTS
SUPERCAPS 0.047F 5.5V 5 for $2
CASED TRANSFORMER 230: 1.7V
300mA AC - in small plastic case
with 2m long input and output
leads: $6
PCB WITH AD7581LN 1C: PCB with
many components with a MAXIM
AD758ILN 1C, 8-bit, 8-channel
memory buffered data acquisition
system designed to interface with
microprocessors, $29.
POWER SUPPLY
Used, clean non-standard computer
power supplies, in perforated metal
casing for air circulation, built-in fan,
I EC input connector and OFF-ON
switch, "flying" DC output leads,
dimensions: 87 x 130 x 328mm,
110-220V input, +5V @ 8A, +12V <§>
3A, and -12V @ 0.25A DC outputs.
BARGAIN: $18 ea. or 4 for $60
CABLES
IEC EXTENSION LEADS: 2m, with
I EC plug and IEC socket $5.
MODULAR TELEPHONE CABLES
4 way modular curled cable with
plugs each end, also a 4m 8-way
modular flat cable with plugs each
end, one of each for: $2
WELLER SOLDERING IRON TIPS
New soldering iron tips for low voltage
Weller soldering stations and mains
operated Weller irons. Mixed popular
sizes and temperatures. Specify
mains or soldering station type: 5 for
$ 10 .
VIDEO TRANSMITTERS
low power PAL standard UHF
transmitters. Have audio and video
inputs with adjustable levels, a power
switch and a power input socket:
10-14V DC/lOmA operation.
Enclosed in a small metal box with an
attached telescopic antenna. Range is
up to 10m with the telescopic
antenna supplied, but can be
increased to approximately 30m by
the use of a small directional UHF
antenna. INCREDIBLE PRICING: $25.
MORE ITEMS & KITS
Poll our (02) 579 3955 or
(02) 579 4985 fax
numbers to find out how
to get our item and kit
lists. MANY MANY MORE
ITEMS AND KITS THAN
THOSE LISTED HERE! Ask
for these lists to be sent
with your next order.
_ KITS
MODEL TRAIN KIT
Run two trains on one track without
collisions! Kit includes 2 IR LEDS,
2 IR detectors, 2 small PCBs and a
controller PCB with on-board
components for LED signal lights.
Also doubles as a crossing
controller with flashing LEDs.
INCREDIBLE PRICING: $20.
SINGLE CHANNEL UHF REMOTE
CONTROL SC Dec. 92, one Tx and
Rx: $45, extra Tx $15.
4-CHANNEL UHF REMOTE
CONTROL KIT: Two Tx & 1 Rx $96.
LOW COST 1-2 CHANNEL UHF
REMOTE CONTROL A single
channel 304MHz UHF remote
control with over 1/2 million code
combinations with provision for a
second channel expansion. The low
cost design includes a complete
compact keyring transmitter kit,
which includes a case and battery,
and a PCB and components kit for
the receiver that has 2A relay
contact output!. Tx kit $10, Rx kit
$20 additional components to
convert the receiver to 2 channel
operation (Extra decoder 1C and
relay) $6. INCREDIBLE PRICES:
complete 1 channel Tx-Rx KIT: $30
complete 2 channel Tx-Rx kit: $36
additional transmitters: $10
MASTHEAD AMPLIFIER KIT: Two
PCBs plus all on-board
components: Low noise (uses
MAR-6 1C), covers VHF-UHF, $18
LASER BEAM COMMUNICATOR
KIT: Tx, Rx, plus IR laser: $60
ELECTRIC FENCE KIT: PCB and
components, includes prewound
transformer: $40
FM TRANSMITTER KIT - MK1 This
complete transmitter kit (miniature
microphone included) is the size of
an AA battery, and is powered by a
single AA battery. Use a two AA
battery holder (provided) as the
case, and a battery clip (shorted)
for the switch. Battery life is over
500 hours!! $11
PLASMA BALL KIT: PCB and
components kit, needs any 240V
light bulb, $25.
BRAKE LIGHT INDICATOR KIT: 60
LEDs, two PCBs and ten resistors,
makes a very bright 600mm long,
high intensity red display, $25.
GARAGE DOOR - GATE REMOTE
CONTROL KIT: Tx $18, Rx $79.
1.5-9V CONVERTER KIT: $6 ea. or
3 for $15.
DOT MATRIX LCDs
Brand new Hitachi LM215 400 X 128
dot matrix liquid crystal displays in an
attractive housing. These have driver
ICs fitted but require an external
controller. Effective display size is 65
x 235mm. Priced at less than 10% of
their real value: $25 ea. or 3 for $60
$215 CCD VIDEO SECURITY
SYSTEM
Mono CCD camera on a small
PCB. Includes auto iris lens.
Works with illumination to 0.1
lux and is IR responsive. This
new camera is nearly 1/2 the
size of the unit previously
supplied, almost match box
size! Can be used in total
darkness with IR illumination:
NEW LOW PRICE $180.
We can also supply with each
camera a used, guaranteed
12V DC green computer
monitor and a simple kit to
convert it to work with the CCD
camera. Monitor $25, kit $10.
A COMPLETE 12V CCD VIDEO
SECURITY SYSTEM FOR $215!!
LASERS
MAINS LASER SPECIAL Includes a
compact potted US made power
supply which can be powered from
110/220-240V AC, a 2-3mW He-Ne
tube, a ballast resistor and
instructions. The power supply
requires 4-6V <® 2mA DC. Brand new
components. Giveaway price: $65
ARGON LASER Large water cooled
ARGON laser that outputs 7W of blue -
green, or 1W of red via an inbuilt Dye
laser. Originally for medical use, has
only had 200 hours of use! $12000
AIR-COOLED ARGONS Used argon-ion
heads with 30-100mW output in the
blue/green spectrum. Includes circuit
details of power supply and other
information: head only: $300
VISIBLE LASER DIODE MODULES
Industrial quality 5mW/670nm laser
diode modules. Overall dimensions:
11mm dia x 40mm long. Have APC
driver built in and need about 50mA
from a 3-6V supply: $60
IMAGE INTENSIFIER TUBES
Used but in excellent condition,
second generation image intensifier
tubes. Can be used to make small
and very sensitive scope that can
produce high resolution pictures in
very low illumination. US made tubes
that produce superior results! $350
to $650
BLEMISHED 3-STAGE TUBES We
have a good number of 40mm three
stage fibre optically coupled 3-stage
image intensifies that have minor
blemishes: Similar to above but three
tubes are supplied already bonded
together: Extremely high gain!! Each
of these tubes will be supplied with
the power supply components only.
See SC Sept. 94. $200 (Back copy
SC Sept 94: $5)
OATLEY
ELECTRONICS
PO Box 89, Oatley
NSW 2223
Phone (02) 579 4985 Fax
(02) 570 7910 or 579 3955
major cards accepted with
phone and fax orders
P&P for most mixed orders
Aust $6.
READER INFO NO. 37
o
ICOM Count on us!
WTRODUCHG THE®
FUST HANDHOD CB
WITH BUILT-ll ■
programmable
Duplex operation for
communication
range usiig repeater
stations.
secau
Innovation keeps ICOM ahead.
At Icom our leadership in CB is built on
innovation. And once again, ICOM is first
with the latest, the new IC-40GX.
The smallest handheld UHF CB and
the first with built-in SELCALL.
Now when you want one-to-
one, uninterrupted
communication, there’s
no need to go to the
extra expense of
retrofitting.
The IC-40GX
allows you to
send or receive
calls from a specific
individual or group.
Each unit is factory-
programmed with its own unique
code and can monitor continuously, in
quiet mode, until a selective call signal is received.
You receive the calls that are specifically for you with no
disturbing outside chatter. It makes UHF CB
simple and as convenient to use as a handphone.
Open Scan/Group Scan
facfity with separate
user programmable
memory.
Your emergency
services channel.
It can be a life
saver.
Simple one touch scan
function: start, stop,
memorise
Feature after feature, ICOM puts you first.
You can program your ten most frequently-called numbers for
single button speed calling. You also get call-back
acknowledgement and Group Call to as many as lvO stations.
There's up to a full 5W of output power with a Hi/Lo
transmission switch to conserve power and a power save
mode on receive. Plus a one touch Channel 5 emergency
channel, and much more.
Discover the innovative features, the clarity and performance
of the new IC-40GX for yourself at your nearest Icom dealer soon.
Icom Australia 7 Duke St Windsor Victoria 3181 A.C.N. 006 092 575
Free Call: (008) 338 915 Ph: (03) 529 7582 Fax: (03) 529 8485
READER INFO NO. 38
L.L. BROWN ADVERTISING 4803
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